New York - Eight people died and 11 injured in the worst terror attack on New York since September 11, 2001 as a lone wolf extremist screaming "Allahu Akbar" used a pick-up truck to mow down cyclists along a bike path on Halloween.
The attacker struck just a few blocks from the site of the World Trade Center memorial, running over afternoon riders on the path before reaching a road and ploughing into a school bus.
He then jumped out of the truck wielding what turned out to be a pellet gun, and a paintball gun. He was chased and shot in the stomach by a police officer but survived and was arrested.
US media, citing police sources, said that Saipov left a note in the truck claiming he committed the attack on behalf of the Islamic State of Iraq and the Levant.
President Donald Trump wrote on Twitter: "Looks like another attack by a very sick and deranged person. Law enforcement is following this closely. NOT IN THE U.S.A.!"
Mr Trump blamed the attack on Islamic State of Iraq and the Levant which has encouraged its followers to use vehicles to mow people down. The UK, France and Germany have all seen deadly vehicle attacks in the recent past.
The US president added: "We must not allow ISIS to return, or enter, our country after defeating them in the Middle East and elsewhere. Enough!"
A White House official said Mr Trump had been fully briefed by his chief of staff John Kelly and was being "continually updated".
Prime Minister Theresa May said she was "appalled by this cowardly attack, my thoughts are with all affected. Together we will defeat the evil of terrorism".
Bill de Blasio, the Mayor of New York, said: "Its a very painful day in our city, a horrible tragedy. This was a particularly cowardly act of terror aimed at innocent civilians going about their lives with no idea of what was about to hit them.
"We know this action was intended to break our spirit. We have been tested before as a city, very near the site of todays attack. We will respond as we always do, we will be undeterred."
The suspect had rented the pick-up truck from a Home Depot hardware shop. He then drove down the bike path for 20 street blocks, running down cyclists, before hitting the school bus. Two children on the bus were among 11 people injured in the attack.
Belgium said one of its nationals was among the people killed.
Witnesses said they initially thought the attack was a Halloween prank.
A man who was riding in a taxi along the West Side Highway near Chambers Street in Lower Manhattan said he saw several people on the ground.
One witness told the Telegraph: "I heard five shots and went over to window and saw people running around. Police and ambulance already at scene."
The incident happened in the area of Chambers and West Streets in the TriBeCa neighbourhood at 3.15pm.
One witness said on Twitter: “Jesus! A car just ran over 2 people and then crashed into a school bus. I see two dead bodies and bikes on the floor destroyed."
Laith Bahlouli, 14, a student at a nearby high school said: “What happened was there was a car crash, he came out of one of the cars. He had two guns. We thought the guns were fake and it was a Halloween prank.
"We thought it was a Halloween thing. He started running around the highway. There was another guy in a green shirt that was chasing him around. I heard four to six gunshots – everybody starts running."