Donald Trump told reporters at the White House on Monday that the office of the Leader of the Islamic Republic of Iran Ayatollah Seyyed Ali Khamenei would be denied access to financial resources by the new sanctions, according to Russia Today.
The new sanctions come a day after the US claimed it launched massive and successful cyber strikes against Iranian military computer systems, although Tehran said Washignton's efforts failed.
Earlier this month, the US accused Tehran of being behind attacks on two oil tankers in the Gulf of Oman, but even US allies Germany and Japan have cast doubt on shaky evidence presented by the Pentagon.
US Treasury Secretary Steve Mnuchin said Trump's executive order will lock up billions of dollars more in Iranian assets.
Mnuchin also promised that Iranian Foreign Secretary Javad Zarif will be hit with sanctions later in the week, adding that the US has not consulted with its allies on the specifics of the planned measures.
The US has claimed that the surveillance drone was shot down in international airspace, while Iran stresses its was destroyed over its own territory.
Earlier, Russia described these new sanctions as illegal, saying it will counter them.
Trump administration unilaterally withdrew from Iran nuclear deal last year in May and re-imposed its secondary sanctions, which have proven to be ineffective to bring Iran back to the negotiating to renegotiate a new deal. Iran has said that it would resume high-level uranium enrichment if the other parties to the deal do not fulfill their commitments by a 60-day deadline that expires in less than two weeks.