A man suspected of killing eight people and injuring at least ten more in a vehicle truck attack left a note pledging allegiance to Islamic State, US media has reported.
Officials have said they discovered the note, which one officer said was written in a foreign language, in the truck Sayfullo Habibullaevic Saipov allegedly drove through a busy Manhattan cycle route on Tuesday afternoon.
The 29-year-old reportedly drove 14 blocks before crashing into a school bus and jumping from the rented truck with two replica guns.
He was then shot in the abdomen by police and is expected to survive after undergoing surgery.
Authorities speaking under anonymity have revealed Saipov, who worked as a truck and Uber driver, was an Uzbekistan national who entered the US legally in 2010. He had lived in Tampa, Florida, and New Jersey.
A family friend, Dilnoza Abdusamatova, told the Cincinnatti Enquirer that he was "really calm" and "wouldn't go to parties or anything".
"He only used to come home and rest and leave and go back to work," he said.
Of the eight people killed in the attack the majority are foreign nationals, with five belonging to the same group from the Argentine city of Roasario.
The friends were visiting New York as part of a 30th anniversary school reunion when they were killed, the country's foreign ministry revealed.
A sixth victim, from Belgium, was announced by foreign minister Didier Reynders in the hours following the attack.
I am deeply saddened to announce a belgian victim in #Manhattan – I express my condolences to the family and friends
— didier reynders (@dreynders) 31 October 2017
Accounts of the incident described a street littered with mangled bicycles and bodies that were quickly covered with sheets after the arrival of scores of police officers.
"I saw a lot of blood over there," Chen Yi, an Uber driver, told Associated Press. "A lot of people on the ground."
Witnesses said some at first thought the attack a Halloween prank.
Sky News US Correspondent Hannah Thomas-Peter who is in Washington said police sources are saying some of those injured may have been unable to get out of the way because they were wearing headphones while cycling.
She said: "It's a very common thing to do in New York City, and it tells me that some of those victims are potentially very young indeed. School finishes at 2.30pm, and the attack happened at 3.05pm."
Photos from the scene showed a badly damaged Home Depot rental pickup truck in the middle of the road.
A 14-year-old student from the nearby Stuyvesant High School told the New York Post: "What happened was there was a car crash… he came out of one of the cars. He had two guns."
We must not allow ISIS to return, or enter, our country after defeating them in the Middle East and elsewhere. Enough!
— Donald J. Trump (@realDonaldTrump) 31 October 2017
President Donald Trump responded to the incident with a series of tweets, first describing the attack as the work of a "sick and deranged person" and saying "we must not allow ISIS to return", before offering condolences to the victims.
He later tweeted: "I have just ordered Homeland Security to step up our already Extreme Vetting Program. Being politically correct is fine, but not for this!".
The President's stringent controls on immigration from certain countries, which have faced staunch opposition, do not refer to Uzbekistan and would not have prevented the suspect from entering the United States.
New York Mayor Bill de Blasio said the attack was "an act of terror, and a particularly cowardly act of terror aimed at innocent civilians, aimed at people going about their lives who had no idea what was about to hit them."
Other officials urged New Yorkers to continue with their lives undeterred, stressing that a heightened security presence was not a sign that further attacks were expected. The city's annual Halloween parade was held as planned on Thursday.
Andrew Cuomo, the city's Governor, described the incident as a "lone wolf" attack and said there was no evidence suggesting it was part of a larger plot.
British politicians also joined global leaders in condemnation.
Theresa May saying she was "appalled by this cowardly attack" while Sadiq Khan tweeted that London stood in "grief and solidarity" with New York.