U.S. President Donald Trump on Thursday reiterated his call that the Uzbek immigrant accused of killing eight people by speeding a rental truck down a New York City bike path should get the death penalty.

The suspect, Sayfullo Saipov, told investigators he was inspired by watching Islamic State videos and began planning Tuesday's attack a year ago, according to the criminal complaint filed in federal court against him on Wednesday.

Saipov, 29, said "he felt good about what he had done" and asked for permission to display the flag of the militant group Islamic State in his hospital room, the complaint said.