The suspect behind a fatal truck attack in New York has boasted about killing people while he recovers in hospital, according to local reports.

The attacker, identified as 29-year-old Sayfullo Saipov, killed eight people and injured another 11 when he rammed a truck into a bike path on 31 October. The man was shot and arrested as he attempted to flee the scene.

When police interrogated him before he underwent surgery, he said he had no remorse for his actions, CBS News reported, quoting unnamed sources.

The suspect, believed to be in stable conditions, reportedly shouted "Allahu Akhbar" ("God is great" in Arabic) before he was shot.

One source said the man made "no bones" about the attack.

The suspect is thought to have acted alone.

Both the New York Police Department and the FBI are working on the case.

Authorities reportedly found a note in the truck used in the attack, claiming the suspect carried out the act in the name of the Islamic State (Isis) terror group.

Another note said "Isis lives forever".

Isis has not claimed responsibility for the massacre.

The suspect, originally from Uzbekistan, is thought to have moved to the US in 2010.

"After he came to the United States is when he started to become informed about ISIS and radical Islamic tactics," Cuomotold the CNN.

"Again, ISIS has gotten it down to a simple formula that they can put on the internet and it doesn't take a rocket scientist to rent a car, rent a truck. But they are cowards and they are depraved."

US President Donald Trump took to Twitter to condemn the attack, which he said was carried out by a "very sick and deranged person".

"We must not allow Isis to return, or enter, our country after defeating them in the Middle East and elsewhere. Enough!" the leader continued.

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