US President Donald Trump has tweeted that the suspect in the New York truck attack that killed eight people should get the death penalty.

Referring to the suspect's nonchalant behavior in the hospital where he was taken after police officers shot him, Trump tweeted: "NYC terrorist was happy as he asked to hang ISIS flag in his hospital room."

NYC terrorist was happy as he asked to hang ISIS flag in his hospital room. He killed 8 people, badly injured 12. SHOULD GET DEATH PENALTY! — Donald J. Trump (@realDonaldTrump) November 2, 2017

Uzbek national Sayfullo Saipov has been formally accused of killing at least eight people and charged with providing material support and resources to the Islamic State terrorist group. He is the main suspect in the Tuesday attack, where he ran a truck along a busy cycle lane in lower Manhattan before ramming it into a school bus. He was then shot in the abdomen by police officers arriving on the scene and taken to a hospital.

READ MORE: US files terrorism charges against NYC attacker, questions 2nd Uzbek man

Saipov has shown no remorse for his actions. On the contrary, he reportedly told law enforcement officials he was inspired to carry out the attack by Islamic State (IS, formerly ISIS/ISIL) videos he watched on his cellphone, and felt good about what he had done. He then asked if he could hang an IS flag in his ward.

Donald Trump's previous comments in the wake of the attack have mostly focused on calling for tougher migration regulations, including "tougher extreme vetting" and a curb on "chain migration," saying that some families that immigrants bring with them can be "truly evil."

The United States will be immediately implementing much tougher Extreme Vetting Procedures. The safety of our citizens comes first! — Donald J. Trump (@realDonaldTrump) November 2, 2017

CHAIN MIGRATION must end now! Some people come in, and they bring their whole family with them, who can be truly evil. NOT ACCEPTABLE! pic.twitter.com/PQGeTTdRtX — Donald J. Trump (@realDonaldTrump) November 1, 2017

The terrorism charges brought against Saipov could indeed result in him being sentenced to death under American law.