Washington — President Trump authorized the targeted killing of Qassem Soleimani, the leader of Iran's elite Quds Force, last summer or fall, two sources familiar with the matter tell CBS News.

NBC News, citing five current and former senior administration officials, reported on Monday that Mr. Trump authorized Soleimani's killing seven months ago if Iran's increasingly belligerent actions led to the death of an American. NBC News said the president reserved the right to greenlight the specific operation himself.

The strike that killed Soleimani ultimately took place January 3, when Mr. Trump ordered a drone strike targeting a convoy carrying Soleimani in Baghdad. In addition to Soleimani, Abu Mahdi al-Muhandis, the leader of the Iranian-backed militia Kataib Hezbollah, was also killed in the attack.

Get Breaking News Delivered to Your Inbox

Soleimani's killing came after months of escalating tensions between the U.S. and Iran, punctuated by a week of violent confrontations. On December 27, an American contractor was killed and four other American service members were wounded in a rocket attack against a military base in northern Iraq. The U.S. blamed the attack on Kataib Hezbollah and retaliated with airstrikes that killed more than two dozen members of the militia.

Those airstrikes sparked two days of protests at the U.S. embassy in Baghdad, as thousands of demonstrators — many of them members of Iranian-backed Shiite militias — descended upon the compound.

Tensions reached a fever pitch the following week with the drone strike targeting Soleimani. Days later, Iran retaliated by launching ballistic missiles at Iraqi bases housing U.S. and coalition forces, though no one was injured in the attacks.

Over the weekend, The New York Times reported that officials had discussed the possibility of taking out Soleimani for the past 18 months. The Times said U.S. intelligence officials focused on developing sources to track Soleimani's travels across the region, with the military becoming involved in planning a potential operation by September.

Mr. Trump has said that he ordered the strike that took out Soleimani after the U.S. received information of "imminent" threats to American personnel in the region. He later told Fox News in an interview that Soleimani was orchestrating an attack on four U.S. embassies, including the embassy in Baghdad.

But Defense Secretary Mark Esper told "Face the Nation" on Sunday that he "didn't see" specific evidence that Soleimani was planning assaults on four embassies, but agreed with the president's belief that they would be targeted.