NEW YORK (AFP) - A hatchet attack on New York police officers was a "terrorist act" carried out by a self-radicalized Muslim convert who had been in the military and browsed Al-Qaeda websites, police said Friday.
"This was a terrorist act," police commissioner Bill Bratton told a news conference on Friday, one day after the attack, saying he was "very comfortable" describing it as a "terrorist attack."
Police said Mr Zale Thompson, 32, unmarried and unemployed, appeared to have acted alone and was not affiliated to a particular group, but that the investigation was ongoing.
A loner who spent hours locked away in his bedroom, he had looked at websites about groups such as Al-Qaeda and Islamic State, and watched beheadings and Wednesday's deadly attack in Canada.
Officer Kenneth Healy, 25, is in hospital in a critical but stable condition after being injured in the back of the head during Thursday's broad daylight attack in a busy shopping area.
Another officer was hit in the arm in the assault in New York's borough of Queens.
The group of four young police officers had graduated from the police academy only months before.
In an attack that lasted just seven seconds, Mr Bratton said Mr Thompson charged with a hatchet in his hand, striking two officers before he was shot dead by the two other officers, who were uninjured.
A graphic video of the attack has been released, showing a bearded Thompson dressed in a green jacket, running towards his victims and swinging the hatchet in both hands.
A 29-year-old female bystander was accidentally shot and is also in hospital in a critical but stable condition, Mr Bratton said.
Police said Mr Thompson converted to Islam two years ago and that relatives described him as a "recluse" and "lately depressed."
An axe and a large hunting knife were recovered from his home and Thompson made anti-Western, anti-government and in some cases anti-white statements on social media, police said.
He visited websites that focused on terror groups such as Al-Qaeda, the ISIS organization and the Shebab Islamists in Somalia.
Police said Thompson's Internet browsing history included the fence-jumping incident at the White House this week and Wednesday's shooting in Canada.