On Jan. 3, 2020, President Trump authorized a U.S. drone strike that killed Iran’s Major General Qassem Soleimani of the Islamic Revolutionary Guard Corps. 

The attack occurred early Friday morning at a Baghdad airport and also killed Abu Mahdi al-Muhandis, a close Soleimani associate.

“General Suleimani was actively developing plans to attack American diplomats and service members in Iraq and throughout the region. This strike was aimed at deterring future Iranian attack plans,” a statement released by the Pentagon after the attack said.

Suleimani was the commander of Iran’s elite Quds force, a wing of Iran’s Revolutionary Guards that Trump labeled a terrorist organization in April 2019. In a statement, the Pentagon accused the Quds of being responsible for the deaths and injuries of hundreds of U.S. service members.

“Under my leadership, America’s policy is unambiguous: to terrorists who harm or intend to harm any American, we will find you; we will eliminate you,” President Trump said in his first public remarks after the killing.

According to The Guardian, many leaders consider Suleimani to be the second most powerful person in Iran behind Ali Khamenei, Iran’s Supreme Leader.

“‘The U.S.’s act of international terrorism, targeting & assassinating General Suleimani – the most effective force fighting Daesh (ISIS), Al Nusrah, Al Qaeda et. al. – is extremely dangerous & a foolish escalation. The US bears responsibility for all consequences of its rogue adventurism,’” Iran’s foreign minister, Mohammad Javad Zarif, said on Twitter.

On Jan. 8, 2020, Iran retaliated by firing over a dozen ballistic missiles at al-Asad, an Iraqi military base housing U.S. troops. No American or Iraqi lives were lost.

“We do not seek escalation or war, but will defend ourselves against any aggression,” Zarif said.

The next day, on Jan. 9, 2020, President Trump moved to de-escalate tensions, stating that the U.S. would take no additional military action.

Also on Jan. 9, House Speaker Nancy Pelosi, D-Calif., passed a resolution seeking to limit Trump’s ability to take military action against Iran. The resolution emphasized that if the president wishes to take the U.S. to war, he or she must first get authorization from Congress; specifically, it instructed the president to terminate the use of U.S. armed forces to engage in hostilities against Iran unless Congress has declared war, enacted a specific authorization or unless military action is necessary due to an imminent attack, according to NBC News.