By Arul Louis 

New York, Nov 2 (IANS): President Donald Trump has called the Uzbek immigrant arrested in Tuesday's terror attack that killed eight persons an "enemy combatant". However, prosecutors filed terrorism charges against him in a civilian federal court here.

Acting federal prosecutor Joon Kim announced the filing of the charges in the civilian federal court on Wednesday, hours after Trump said that he would be open to sending Sayfullo Saipov to the military prison in Guantanamo Bay, where terrorists captured abroad are tried by military tribunals.

At the start of a cabinet meeting, in reply to a reporter's question about the possibility of Saipov being sent to Guantanmo, Trump said: "Send him to Gitmo -- I would certainly consider that, yes."

Sending Saipov, 29, a legal immigrant with a green card, to Guantanamo for a military trial may raise legal questions while labelling him an "enemy combatant" may open the way for this.

Guantanamo, known as Gitmo for short, is a US military base in Cuba -- in territory under American control.

Saipov mowed down pedestrians and bicyclists with a rented truck on Tuesday. The rampage ended when the truck hit a school bus.

After he emerged from it brandishing two fake guns, a police officer shot and arrested him.

Six of those killed were foreign tourists. Twelve people were injured.

The initial charges filed against Saipov are only about providing support to a terrorist organisation, the Islamic State (IS), and operating a motor vehicle in a manner that caused a death.

These charges were meant to hold him in custody. More serious charges about the killing of eight people and other actions were expected later.

New York state does not have death penalty but because he is charged in a federal court and not a state court, Saipov can face capital punishment under federal laws.

The court papers said Saipov told officials in hospital that he felt "good" about what he had done and asked them to put an IS flag in his hospital room.

He told the officials that he was inspired by IS leader Abu Bakr al-Baghdadi and had planned the attack more than a year ago, choosing Halloween day because he thought he could do the maximum damage then.

About a week before the attack, he told the officers, he had made a trial run of the area near the 9/11 memorial and had planned to continue his attack on the Brooklyn Bridge. But he could not because of the collision with the school bus.

Officials said in the court document that on Saipov's cellphones they found about 90 IS videos with bomb-making instructions and showing beheading of prisoners and running them over with tanks.

Earlier at a news conference, New York Police Counter-terrorism Deputy Commissioner John Miller said Saipov "appears to have followed almost to a 'T' the instructions that IS has put out" for carrying out vehicle attacks.