The main suspect in the New York truck rampage that killed eight people on Tuesday has told investigators he began planning the attack a year ago.

Sayfullo Saipov, 29, said he intended to kill as many people as possible and "felt good" about the Halloween attack.

The Uzbek immigrant, who faces federal terrorism charges, says he was inspired by so-called Islamic State. He was shot and injured by police at the scene.

US President Donald Trump tweeted that he should receive the death penalty.

The charges filed against Mr Saipov are federal, which means the government can override New York state's ban on capital punishment.