President Donald Trump has signed an executive order authorizing new sanctions against the Iranian regime in response to Iran shooting down a U.S. drone on Thursday.

What's the background?

On Thursday morning, Iran shot down an American RQ-4A Global Hawk drone. Iran claimed that the drone had violated its airspace. The U.S. has insisted that it was over international waters and called this an "unprovoked attack."

The same day, Trump prepared to launch a counterstrike against Iran. However, just minutes before the attack was going to be carried out, he called it off. In a tweet, he said that he had decided against the strike after a general told him that 150 people would be killed. Monday's sanctions were imposed as an alternative form of retribution, in place of the strike.

What happened now?

"The Supreme Leader of Iran is one who ultimately is responsible for the hostile conduct of the regime. He's respected within his country. His office oversees the regime's most brutal instruments, including the Islamic Revolutionary Guard Corps," Trump said on Monday.

"Sanctions imposed through the executive order that I'm about to sign will deny the Supreme Leader and the Supreme Leader's Office, and those closely affiliated with him and the office, access to key financial resources and support. The assets of Ayatollah Khamenei and his office will not be spared from the sanctions."

Trump said that the sanctions were the result of "a series of aggressive behaviors by the Iranian regime in recent weeks" including the downing of the drone, and the bombing of oil tankers in the Gulf of Oman. Without offering details, Trump added "we know of other things that were done also, which were not good and not appropriate."

Trump added that Iran's Supreme Leader had "the potential to have a great country, and quickly. Very quickly," but that at the moment he was on a "very destructive path."