By Estelle Shirbon and William James

LONDON (Reuters) - Three attackers drove a van into pedestrians on London Bridge before stabbing revellers nearby on Saturday night, killing at least seven people in what Britain said was the work of Islamist militants engaged in a "new trend" of terrorism.

At least 48 people were injured in the attack, the third to hit Britain in less than three months and occurring days ahead of a snap parliamentary election on Thursday.  

Police shot dead the three male assailants in the Borough Market area near the bridge within eight minutes of receiving the first emergency call shortly after 10 p.m. local time.

"We believe we are experiencing a new trend in the threat we face as terrorism breeds terrorism," Prime Minister Theresa May  said in a televised statement on Sunday in front of her Downing Street office, where flags flew at half-mast.

"Perpetrators are inspired to attack not only on the basis of carefully constructed plots ... and not even as lone attackers radicalised online, but by copying one another and often using the crudest of means of attack."

She said the series of attacks represented a perversion of Islam and that Britain's counter-terrorism strategy needed to be reviewed, adding: "It is time to say enough is enough." 

Most of the main political parties suspended national campaigning on Sunday, but May said campaigning would resume on Monday and that the election would go ahead as planned. 

London Bridge is a major transport hub and nearby Borough Market is a fashionable warren of alleyways packed with bars and restaurants that is always bustling on a Saturday night.

The area remained cordoned off and patrolled by armed police and counter-terrorism officers on Sunday, with train stations closed. Forensic investigators could be seen working on the bridge, where buses and taxis stood abandoned. 

There was no immediate claim of responsibility for the latest attack to hit Britain and Europe.

Less than two weeks ago, an Islamist suicide bomber killed 22 people including children at a concert by U.S. singer Ariana Grande in Manchester in northern England. In March, in a attack similar to Saturday's, a man killed five people after driving into pedestrians on Westminster Bridge in central London.

Grande and other acts were due to give a benefit concert at Manchester's Old Trafford cricket ground on Sunday evening to raise funds for victims of the concert bombing and their families. Police said the event would go ahead as planned, but security would be increased. 

The three attackers on Saturday night were wearing what looked like explosive vests that were later found to have been fake. May said the assailants' aim had been to sow panic. The BBC showed a photograph of two possible attackers shot by police, one of whom had canisters strapped to his body.

Home Secretary Amber Rudd said it did not appear that there was a link between the attackers and the Manchester bombing.

Islamist militants have carried out attacks in Berlin, Nice, Brussels and Paris over the past two years.

STAB WOUNDS

The London Ambulance Service said 48 people had been taken to five hospitals across the capital and a number of others had been treated at the scene for minor injuries.

London Mayor Sadiq Khan said some of those who had been injured were in a critical condition. He said the official threat level in Britain remained at severe, meaning a militant attack is highly likely. It had been raised to critical after the Manchester attack, then lowered again days later.

"One of the things we can do is show that we aren't going to be cowed is by voting on Thursday and making sure that we understand the importance of our democracy, our civil liberties and our human rights," Khan said.

Roy Smith, a police officer who was at the scene during the unfolding emergency, expressed his shock on Twitter.

"Started shift taking photos with children playing on the South Bank. Ended it giving CPR to innocent victims attacked at London Bridge," he wrote, adding a broken heart emoji.

Witnesses described a white van careering into pedestrians on the bridge.

"It looked like he was aiming for groups of people," Mark Roberts, 53, a management consultant, told Reuters. He saw at least six people on the ground after the van veered on and off the pavement. "It was horrendous," he said.

A taxi driver told the BBC that three men got out of the van with long knives and "went randomly along Borough High Street stabbing people." Witnesses described people running into a bar to seek shelter.

"People started running and screaming, and the van crashes into the railing behind. We went towards Borough Market and everyone went inside (the bar)," one witness, who gave his name as Brian, 32, told Reuters.

Another witness, who declined to be named, described a scene of panic in the bar.

"They hit the emergency alarm. There was a line of people going down to the emergency exit. And then people started screaming coming back up," said the 31-year-old, his white top covered in blood. 

"Around the corner there was a guy with a stab wound on his neck ... There was a doctor in the pub and she helped him. They put pressure on the stab wound."

BBC radio said witnesses saw people throwing tables and chairs at the attackers to protect themselves.

SOLIDARITY FROM WORLD LEADERS

Islamic State, losing territory in Syria and Iraq to an advance backed by a U.S-led coalition, had sent out a call on instant messaging service Telegram early on Saturday urging its followers to launch attacks with trucks, knives and guns against "Crusaders" during the Muslim holy month of Ramadan.

British Prime Minister May was due to chair a meeting of the government's Cobra security committee later on Sunday.

U.S. President Donald Trump took to Twitter to offer help to Britain while Russian President Vladimir Putin expressed condolences in a telegram to May. [L8N1J10AH]

German Chancellor Angela Merkel voiced her sympathy. 

"Today, we are united across all borders in horror and sadness, but equally in determination. I stress for Germany: in the fight against all forms of terrorism, we stand firmly and decisively at the side of Great Britain," she said.

French President Emmanuel Macron said on Twitter that "France is standing more than ever side by side with the UK".

Four French nationals were among those injured in the London attack, French officials said. Australia said two of its citizens were caught up in it and one of them was in hospital.

The Manchester bombing on May 22 was the deadliest attack in Britain since July 2005, when four British Muslim suicide bombers killed 52 people in coordinated assaults on London's transport network.

 (Additional reporting by Dylan Martinez, UK Bureau and Marine Pennetier; writing by Pravin Char; editing by Mark Heinrich)

Princess Diana captured the world's imagination, so much so, many thought they really knew her. The reality is, they just knew a part of the Diana story. CBS News explores the public and private life of a complex woman and the lingering questions surrounding her death. 

"Her name was Diana and the world fell in love with her," "CBS This Morning" co-host Gayle King says in "Princess Diana: Her Life | Her Death | The Truth" airing Monday at 8/7c on CBS. "But her fairy tale life also had a heartache – it did not have a happily ever after ending."

This summer it will be 20 years since the death of Diana, Princess of Wales. To mark the anniversary, King anchors the broadcast from Althorp, the princes

s's family estate in England. Through the words of those who knew her, who admired her, in her own words, and through the rich archive of CBS News, the special looks at the impact Princess Diana had on Britain, the monarchy and the world and features interviews with close friends who open up about their personal conversations Princess Diana in the weeks leading up to her death. In fact, friend Lana Marks reveals something surprising -- the man who was the only one true love of her life.

From her wedding to Prince Charles in 1981 until her tragic death on Aug. 31, 1997 in a horrific car crash in the Pont de I'Alma road tunnel in Paris, Princess Diana was a public draw, but there was much more behind the headlines most people never knew.

"I think Diana's death robbed the world of an extraordinary, luminous character," says author Patrick Jephson. "She leaves an unfillable gap on the world stage."

Behind the crown and the designer dresses, Diana was a complicated and occasionally unpredictable woman, say those who knew her best.  "She always said, 'I want to be normal,'" says Ken Wharfe, her former bodyguard. "The tragedy is, with being a member of the royal family, it's almost impossible to be normal."

She was far from normal. In fact, the marriage that captured the hearts of people around the world was a struggle. In public they played their parts, but in private it was a different story. They would fight, says author Sally Bedell Smith, and she would taunt Prince Charles by telling him he'd never be king.

"And there was one moment when they were having a big fight, and he was down on his knees praying, and Diana was hitting him even as he was praying," Bedell Smith says. "That was the kind of intensity of the discord that they had."

Just as the world watched as Prince Charles and Diana married, they watched as the marriage unraveled. They also followed along as Princess Diana reemerged in public life alone after the divorce and right up until she died. At the time, the summer of 1997 was supposed to be a time of self-discovery and new beginnings. She was no longer a member of the royal family and was dating businessman Dodi Al Fayed. It all ended when they piled into a Mercedes and sped off from the Ritz hotel in Paris with paparazzi chasing them.

When the Mercedes reached the Pont de I'Alma road tunnel, driver Henri Paul lost control. He sideswiped a slower moving white Fiat that drove off.

Her death was just as controversial as her life. Almost immediately conspiracy theories were raised about what happened. Were the paparazzi somehow responsible? Had someone tampered with the Mercedes? What about that white Fiat? Did the driver intentionally cause the crash? And what could have been done to prevent the crash?

After losing his right forearm in a factory accident, Chang Hsien-Liang tried several artificial limbs but he was never satisfied.

The arms he could afford were too basic and the robotic hand he wanted was too expensive.

So the 46-year-old engineer from southwest Taiwan set out to design and build his own prosthetic arm using 3D printing technology.

"After getting my own bionic arm, my daily life improved. It became easier to do things like riding a bike and eating a meal," Chang said in an interview.

At the time of his accident in September 2014, Chang was working as a metal engineer at a stamping plant in Tainan City, about 300 km (186 miles) southwest of the capital Taipei.

Chang said he accidentally pressed the wrong button when operating a stamping machine, leaving his right hand so badly injured it had to be amputated.

Two months after the accident, Chang tried two prosthetic arms but was disappointed. He wanted a hand with moveable fingers but could not afford the thousands of dollars for a custom-made arm.

Chang heard about 3D printing technology and acquired a scanner and printer. With no medical training, he watched online videos to learn about fingers and hands.

After many attempts, Chang said he produced an arm with moveable fingers that cost about $4,000.

"I was very happy and excited, finally my design could be used," he said.

Now, Chang wants to help others.

He is designing and building a prosthetic hand for Angel Peng, an 8-year-old girl whose hand was crippled in a scalding accident when she was nine months old. Her mother Peng Ji-han said they heard about Chang at Angel's clinic.

"She grew up thinking it is normal not to have one hand," Peng said, adding she could not afford an expensive prosthetic for her daughter.

Angel's eyes widened excitedly as she tried to use an early product of Chang's 3D printing to pick up a bottle.

She said she could hardly wait to use her new hand.

"When my hand is done, I will hop onto a bike immediately," she said. 

MILAN (Reuters) - European shares rose slightly in early deals on Friday, timidly recovering from heavy losses suffered earlier this week after U.S. political turmoil fuelled worries over U.S. President Donald Trump's stimulus plans, denting risk appetite.

The pan-European STOXX 600 index rose 0.3 percent by 0725 GMT, but was down  1.5 percent on the week, its biggest weekly loss since early November. Britain's FTSE was up 0.4 percent and euro zone blue chips added 0.3 percent.

While gains were spread across all sectors, pharma stocks and financials gave the biggest boost to the STOXX with shares in heavyweight drugmaker Roche up 0.6 percent, helped by a Barclays price target upgrade, and Spanish lender Banco Santander up 0.8 percent. 

Among the biggest movers was Dufry, up 6.9 percent after luxury group Richemont  bought a 5 percent stake in the company.

Hikma shares fell 4.9 percent after the drugmaker trimmed its revenue forecast to account for the delay in its U.S. generic drug launch.

This week's losses have pulled the stocks down from 21 month highs hit after a run driven by big fund inflows into Europe, solid macro data and surprisingly strong corporate earnings. 

With 80 percent of European companies having reported so far, 65 percent of them have beaten expectations and 8 percent have met them, according to I/B/E/S data. First quarter earnings growth is seen at 19.4 percent, slightly below the more than 20 percent previously forecast.

 (Reporting by Danilo Masoni, Editing by Helen Reid)