A lorry, driven into a crowd during Bastille Day celebrations in the French city of Nice, has killed at least 84 people and critically injured at least 18 more.
Witnesses have been describing the scenes of terror and panic as the tragedy unfolded, and the moment the police managed to stop and kill the driver of the truck.
'He pulled out a gun'
Nader El Shafei told the BBC he looked the attacker in the face for about a minute before witnessing the final gun battle.
"We thought at the beginning it was just an accident," he said, "but then I saw him pulling out his gun and trying to shoot a group of policemen who were coming running towards him.
"I saw him for about one minute - face to-face - but he was not looking at me. He was looking out of the window, appearing very nervous.
"I kept yelling at him, waving with my hand, trying to tell him that there were a lot of dead people underneath his truck. But he did not give any attention to anyone outside the truck.
"Police killed him straight away - they didn't wait to negotiate - they just opened fire on him."
'Motorcyclist tried to stop him'
German journalist Richard Gutjahr witnessed the start of the attack and described seeing a motorcyclist pursue the truck and try to gain entrance to its cabin. But the biker fell off and was run over by its wheels.
"I stood on the balcony on the Promenade des Anglais, and saw people celebrating there [when] suddenly a truck drove through the crowd," Mr Gutjahr, 42, told the AFP news agency.
"Surprisingly, [the truck driver] drove very slowly and was chased by a motorcyclist.
"The motorcyclist attempted to overtake the truck and even tried to open the driver's door, but he fell and ended up under the wheels of the truck."
Simon Coates, a British lawyer on holiday in Nice, was cycling along the promenade with his wife back to their apartment after the fireworks when the lorry sped past them into the crowds. In the chaos he was separated from his wife.
"I turned round and followed the path the lorry took checking the people killed to see if she was one of them," he told the BBC.
"I had to check every body and they were so disfigured the only reliable way I could check was to look for her bike and her shoes as most people were not recognisable."
"People were disembowelled, stripped naked of their clothes, mothers sprawled on the floor next to their dead children; one person was wrapped up like a Swiss roll with his arms and legs sticking out from his body which was folded back on itself," he said.
"When I caught up with the lorry it was stationary and an armed policeman was pointing a gun at the passenger side; others were taking cover and getting people away as they suspected a bomb.
"I retraced my steps and thank God I found my wife unharmed at home."
'Lots of bodies'
US Citizen Julie Holland, on holiday in Nice with her two daughters, told The Guardian that she saw the truck driving at full speed through the crowds on the promenade.
"We heard screams, and people started running into the restaurant," she said. "We hid in the kitchen, behind a stove.
"As soon as the gunfire stopped we went through the back door to a hotel down the street. A policeman eventually escorted us back to our hotel at around 3am. There were bodies everywhere. My daughters saw bodies. Lots of them."
'Swerving all over the place'
Pouya from Toronto in Canada told the BBC that people were enjoying the carnival atmosphere on the promenade created by a firework display and a jazz band when he heard "lots of screams" and people running in different directions.
"I didn't know what was going on, it felt surreal and I didn't move but thought it must be some kind of practical joke.
"Then I saw the truck coming straight at me swerving all over the place. It was perhaps 50 yards away. After that there was no conscious thought, my body took over, time slowed down and I ran and thank God I got out of the way.
"I jumped into a doorway and a very nice Frenchman let me and about 15 other people into his apartment. We stayed in there for a while and then when it was safe we left. There were lots of panicked people, dead bodies were in the street and there were police everywhere."
Nice resident Ak told the BBC that he and his wife were walking near the Palais de la Mediterranee hotel about 10 minutes after the firework display when he spotted the speeding truck coming towards them.
"We literally had one or two seconds to get away and I just managed to push me and my wife on the pavement," he said.
"We looked back and there was carnage, absolute carnage, and went back to try and help the people on the floor and then we heard the gunshots so we of course decided to run for cover."
'I waited to die'
Imad Dafaaoui, a Moroccan university student, told ABC News of his close brush with death.
"I saw a huge truck, crushing over people," he said. "Some people were trying to get out the way. Some people were in shock. I started to run away. I was in shock.
"I couldn't even think. I was running. There was a bench in front of me, so I had to jump over it, so I jumped over it and fell over on a woman.
"That's when the truck was coming toward me. I just closed my eyes. It was so close. I was just waiting to die. The truck was really close to me. [It] crashed [into] the bench. It was 20cms away from me.
"I'm really glad that I'm alive."
'A lot of confusion'
Paddy Mullan, from Northern Ireland, told the BBC that he had "never seen" such fear.
He said the truck "came out nowhere" and started "ploughing" into the crowd.
"This lorry just mounted the kerb, across the street from us and the next thing, all you could hear was banging and shouting and screaming," he said.
"There was a lot of confusion, misdirection, because we didn't know what exactly was happening, why it was happening."
Mr Mullan said he and his girlfriend "bailed out" of the restaurant through a side exit in order to get to a safer position, going through barriers into an apartment complex behind the building.
"We were pushing all the buzzers to try and get into the apartment blocks," he said. "Eventually we got in."
Kayla Repan, a visitor from the US, was among the hundreds who had gathered to watch the celebrations and fireworks. "The whole city was running," she told Associated Press. "I got extremely frightened and ran away from the promenade. It was chaos."
'Like bowling pins'
Damien Allemand, a journalist with the local newspaper Nice Matin, was at the waterfront after the fireworks had finished.
"A fraction of a second later, an enormous white truck came along at a crazy speed, turning the wheel to mow down the maximum number of people," he said.
"I saw bodies flying like bowling pins along its route. Heard noises, cries that I will never forget."
'Nobody was moving'
British tourist Kevin Harris was in a hotel overlooking the scene of the tragedy.
"I heard a lot of screaming and shouting," he said. "I came out onto my terrace and in front of me I could see lots of what appeared to be bodies lying on the road just outside of where I'm sitting now actually."
London-based Lawyer Harjit Sarang and her children were among those caught up in the terror. She tweeted:
'Like a battlefield'
Another witness, Tarubi Wahid Mosta, posted a video on Facebook which showed photos of an abandoned doll and pushchair. He said that he had come home with a victim's Yorkshire terrier.
"I almost stepped on a corpse, it was horrible. It looked like a battlefield," he said, while describing the sense of helplessness surrounding the carnage.
"I live 200 metres from the promenade and it took nearly one and a half hours to get back to my flat because all the roads have been closed down," BBC producer Roy Calley said as news of the attack unfolded.
"The police have completely taken over the city, the promenade has now been closed down. Everybody was physically pushed away from the site and told to get back in no uncertain terms by the police.
"It had been a normal evening and we were just walking around," Joel Fenster told the BBC. "Suddenly people started running, there were screams and police sirens and policemen shouting at us to evacuate.
"It was terrifying, especially because we didn't know what was going on. At the time we only had heard some kind of gunshots and we assumed that there were people running around with guns.