President Trump on Thursday backed away from his proposal to send the Manhattan terrorist suspect to Guantanamo Bay, and said justice might be delivered to Sayfullo Saipov more quickly in the United States.

"Would love to send the NYC terrorist to Guantanamo but statistically that process takes much longer than going through the Federal system ... There is also something appropriate about keeping him in the home of the horrible crime he committed. Should move fast. DEATH PENALTY!" Trump tweeted Thursday morning.

White House press secretary Sarah Sanders told reporters on Wednesday afternoon that Trump would consider designating Saipov as an "enemy combatant," but said his earlier comment about sending him to the island prison was not intended to be serious.

"I believe he was addressing his frustration with the lengthy process that often comes with a case like this," Sanders told reporters at the White House.

Due to Guantanamo's longer-than-normal court process, Trump believes the 29-year-old green card recipient may see justice faster if he is processed in one of the states he has resided or in New York, where the crime was committed.

Late Wednesday, Trump reiterated his calls for Saipov to be sentenced to death if convicted of killing eight people and wounding 12 others by running people down with a truck Tuesday.