In an exclusive interview with ABC News to mark his 100th day in office, President Donald Trump on Tuesday said he "could" secure the return of Kilmar Abrego Garcia, the Maryland man his administration said in court was mistakenly deported to El Salvador.

"Now the Supreme Court has upheld an order that you must return him to the-- facilitate his return to the United States. What are you doing to comply?" ABC News anchor and Senior National Correspondent Terry Moran asked Trump in the Oval Office.

"Well, the lawyer that said it was a mistake was here a long time, was not appointed by us-- should not have said that, should not have said that," Trump argued. The president then said that Abrego Garcia is a member of the criminal MS-13 gang and "is not an innocent, wonderful gentleman from Maryland." Abrego Garcia's lawyers have maintained he's not MS-13 and has not been charged with or convicted of a crime.

"I'm not saying he's a good guy. It's about the rule of law. The order from the Supreme Court stands, sir," Moran told the president.

"He came into our country illegally," Trump maintained.

"You could get him back. There's a phone on this desk," Moran told Trump, pointing to the phone on the Resolute Desk.

"I could," Trump conceded.

"You could pick it up, and with all--" Moran began to say.

"I could," Trump said again.

"--the power of the presidency, you could call up the president of El Salvador and say, 'Send him back right now,'" Moran explained.

"And if he were the gentleman that you say he is, I would do that," Trump offered, before saying, "I'm not the one making this decision."

"You're the president," Moran told him.

"I-- no, no, no, no. If-- follow the law. You want me to follow the law. If I were the president that just wanted to do anything, I'd probably keep him right where he is—" Trump said.

"The Supreme Court says what the law is," Moran said.

Trump replied, referencing immigration, saying he "was elected to take care of a problem" that was an "unforced error that was made by a very incompetent man," – an apparent jab at President Joe Biden.