Secretary of State Mike Pompeo defended Tuesday the legality of the US drone strike that killed Iranian General Qasem Soleimani and any future military action against Iran.

"I have never seen this administration engage in an activity of this nature without a thorough and complete legal review of what the basis would be if the president were to make a serious decision," Pompeo told reporters.

But Pompeo gave no new information to support the original claim that Soleimani was killed based on information that he planned "imminent" action that threatened American citizens.

Instead, Pompeo appeared to downplay the "imminent" claim, which both he and President Donald Trump had used last week to justify the strike.

Instead he focused on Soleimani's past actions in Iraq, Lebanon and Syria.

"There has been much made about this question of intelligence and imminence," Pompeo told reporters at the State Department.

US Secretary of State Mike Pompeo says he often disagreed with John Bolton
US Secretary of State Mike Pompeo says he often disagreed with John Bolton AFP / MANDEL NGAN

"So if you're looking for imminence, you need only look at the days that led up to the strike that was taken against Soleimani," he said.

Soleimani was killed in a drone-fired missile strike on his SUV just outside the international airport in Baghdad on Friday, where he had arrived from Syria.

The killing sparked outrage in Iran and among Soleimani's large body of Shiite supporters in Iraq, where he wielded much political influence.

Asked whether lawyers were consulted ahead of the strike, Pompeo said he did not know of the specifics.

"Often the lawyers review all of the options that are being presented to the president of the US in advance of them being presented," ensuring full legal vetting, the top US diplomat said.

"I'm confident that was the case here, although I don't have specific knowledge of that," he said.

US Secretary of State Mike Pompeo says that he has shared evidence that Iran carried out an attack on Saudi Arabia
US Secretary of State Mike Pompeo says that he has shared evidence that Iran carried out an attack on Saudi Arabia AFP / Bryan R. Smith

He ridiculed Iranian Foreign Affairs Minister Javad Zarif's assertion that Soleimani -- a commander in charge of external relations for Iran's Islamic Revolutionary Guard Corps -- was on a diplomatic mission while he was in Baghdad.

"Anybody here believe that? Is there any history that would indicate that it was remotely possible that this kind gentleman, this diplomat of great order Qasem Soleimani, had traveled to Baghdad for the idea of conducting a peace mission?"

Pompeo rejected as well the story that Soleimani was travelling to help with a peace deal backed by the Saudi Arabian government.

"We know that wasn't true. We not only know to the history, we know in that moment that was not true," he said.

Asked about President Donald Trump's threat to attack Iranian cultural sites if Tehran retaliates for Soleimani's death, Pompeo said anything the United States does will adhere to the international rules of war.

A number of experts have said that deliberately attacking Iranian cultural sites would constitute a war crime.

"Every target that is being reviewed, every effort that is being made, will always be conducted inside the international laws of war," Pompeo said.

"It's completely consistent with what the president has said."

On Twitter later, Pompeo said the United States had "great respect for Persian history and its symbols, like Persepolis, Naqsh-e Jahan Square and the Tomb of Cyrus."

But he charged that Iran's Islamic Republic "has defiled everything Iranians hold dear."

"No one has damaged Persian culture more than the Islamic Republic -- disrespecting Cyrus and holidays like Nowruz, prohibiting dancing, and putting an end to religious tolerance."