Trump imposes 'hard-hitting' sanctions on Iran's supreme leader after drone attack

“We do not seek conflict with Iran or any other country," Trump told reporters gathered at the White House. "I can only tell you, we cannot ever let Iran have a nuclear weapon."

The sanctions will deny Iranian Supreme Leader Ali Khamenei and those closely affiliated with him and his office from accessing financial resources and support under U.S. jurisdiction, Trump said.

"These measures represent a strong and proportionate response to Iran's increasingly provocative actions," the president said.

"We will continue to increase pressure on Tehran until the regime abandons its dangerous activities and aspirations, including the pursuit of nuclear weapons, increased enrichment of uranium, development of ballistic missiles, engagement and support for terrorism, fueling of foreign conflicts and belligerent acts directed against the United States and its allies."

The sanctions were announced days after Iran's Revolutionary Guard shot down a U.S. surveillance drone flying over the Strait of Hormuz. Iranian officials said the drone had been hovering over the country’s airspace, though U.S. officials said the drone was over international waters when it was shot down.

Last week, Trump ordered a military strike in retaliation for the incident. He said on Twitter that he pulled back from the plan minutes before planes were set to launch after he learned that 150 civilians were expected to die in the attack.

Tensions have been escalating since Trump last year withdrew the U.S. from a global nuclear deal with Iran and re-imposed economic sanctions on Iran.

Iran has decried the U.S. sanctions, which essentially bar Iran from selling its oil internationally, as "economic terrorism."

The Associated Press contributed to this report.