The administration is also sanctioning eight senior Iranian officials who were involved in Tuesday's strike, Mnuchin said. He led the country's Quds Force, which carried out military operations outside of Iran.
Trump's comments came hours after U.S. Secretary of State Mike Pompeo also told reporters that the killing was in response to an "imminent threat". "We still need to focus minds, but it's probably coming soon", a European Union diplomat said before Friday's emergency meeting.
Iran this week launched the strikes in retaliation for the United States drone strike that killed General Qassem Soleiman, the head of the powerful Quds Force, in Baghdad last week.
He was also asked about the contradiction between the administration's insistence that intelligence should be trusted and the myriad attacks Trump has launched against members of the intelligence community who investigated him in conjunction with former special counsel Robert Mueller's Russian Federation probe.
"We don't know exactly which day it would've been executed but it was very clear, Qassem Soleimani himself was plotting a broad, large-scale attack against American interests and those attacks were imminent", Pompeo said.
Iran held to the terms of that agreement, but Trump and Pompeo objected to what they viewed as its generosity and what they called its failure to constrain Iran's other malign activities and ballistic missile program.
Pompeo said that lawmakers were wrong when they said they hadn't been briefed on potential embassy attacks.
This is Maajid Nawaz's incredibly powerful speech on whether President Trump did the right thing by killing Qassem Soleimani.
U.S. to deploy thousands of additional troops to Middle East
As leader of the Quds Force, the foreign arm of the Revolutionary Guards, Soleimani had a key role in fighting in Syria and Iraq. However, many Iraqis criticised Washington for killing the men on Iraqi soil and possibly plunging Iraq into another war.
Angry and hurt: British royals disappointed as Harry and Meghan quit
The final clip shows them leaving the event with goodbyes from the staff and paparazzi flashes as they walk back outside. A spokesperson for Buckingham Palace quickly issued a brisk statement that the transition was still "at an early stage".
Iran launches large attack on US-led forces in Iraq, Pentagon says
Iran's foreign minister wrote on Twitter that the attack was carried out in self-defense after the USA killed Gen. The disaster took place hours after Iran launched its missile attack on USA forces.
Democrats and Republicans on Capitol Hill have spent the week seized with the question of whether Trump was justified in taking out Iranian Gen. Qassem Soleimani, a drastic step that instantly triggered a tidal wave of fury across the Middle East and put the USA and Iran on a war footing.
Pompeo's comment that US embassies were being targeted echoed statements President Trump made at a Thursday campaign rally in Toledo, Ohio.
"What President Trump did is he smoked out Iran, ended the global conceit, this pretence that Iran wasn't backing terrorist militia across the world, by basically holding the top general responsible for all these terrorist militia, accountable for his actions".
Define what you mean by imminent?
"I said how many died, how many were wounded".
"We haven't discussed whether [the dispute resolution process] should be triggered or not", Borrell said. "The intelligence community is not flawless".
"If we didn't have these sanctions in place, literally Iran would have tens of billions of dollars".