WASHINGTON - U.S. officials say special operations forces have captured a key militant in the 2012 Benghazi attack on a U.S. consulate that left four Americans dead, CBS News national security correspondent David Martin confirms.

A U.S. official identified the suspect as Mustafaal-Imam, Martin reports.

The commandos captured the man in Libya just before midnight local time on Sunday and are transporting him back to the U.S., officials told The Associated Press. The suspect is in the custody of the Department of Justice and is expected to arrive within the next two days on a military plane, according to one of the officials.

The officials said the mission was approved by President Donald Trump and done in coordination with Libya's internationally recognized government. The officials, who weren't authorized to speak publicly to the matter and demanded anonymity, would not say where exactly he was captured.

In a statement Monday, Mr. Trump said al-Imam will face justice for his alleged role in the attack.

"To the families of these fallen heroes: I want you to know that your loved ones are not forgotten, and they will never be forgotten," Mr. Trump said. 

The Sept. 2012 assault killed Ambassador Chris Stevens, U.S. State Department computer expert Sean Smith and CIA contractors Glen Doherty and Tyrone Woods.

Stevens and Smith died in the burning diplomatic outpost despite efforts to rescue them. Woods and Doherty died nearly eight hours later in a mortar attack on a nearby CIA complex.

The Associated Press contributed to this report