New sanctions take aim at Iran Supreme Leader

"The assets of Ayatollah Khamanei and his office will not be spared from the sanctions. These measures represent a strong and proportionate response to Iran's increasingly provocative actions. We will continue to increase pressure on Tehran, until the regime abandons its dangerous activities and aspirations," Trump said.

The president then listed the "provocative" actions as "the pursuit of nuclear weapons, increased enrichment of uranium, development of ballistic missiles, engagement with and supporting terrorism, fueling of foreign conflicts, and belligerent acts directed against the United States and its allies".

“These sanctions have been very effective in cutting off funds going to the IRGC [Iranian Revolutionary Guard Corps] and other people….these are highly, highly effective in locking up the Iranian economy,” US Treasury Secretary Steve Mnuchin told reporters, following Trump’s signing of the executive order. 

Mnuchin said the sanctions had “locked up tens and tens of billions of dollars”.

When asked whether the new rounds of sanctions were responding directly the oil tankers or the downing of the drone, Mnuchin said some “were in the works” previously and some were “because of recent activities”. 

Mnuchin said the president had also instructed him that the US would be imposing sanctions on Iran’s Foreign Minister Javad Zarif later this week.

The US Treasury Department said sanctions had also been imposed on eight senior commanders of Navy, Aerospace, and Ground Forces of the IRGC, including Naval Force Commander Alireza Tangsiri, Ground Forces Brigadier-General and Commander Mohammad Pakpour, and Aerospace Force Commander Amir Ali Hajizadeh. 

“These commanders sit atop a bureaucracy that supervises the IRGC’s malicious regional activities, including its provocative ballistic missile program, harassment and sabotage of commercial vessels in international waters, and its destabilizing presence in Syria,” the department said in a statement.

The US withdrew from the Joint Comprehensive Plan of Actions (JCPOA), otherwise known as the 2015 nuclear deal, in May 2018. Following a 180 day wind-down period, the US imposed sanctions that primarily targeted Iran's oil industry.

The sanctions have dealt a massive economic blow to Iran's economy.The national currency has lost around 70 percent of its value, and rates of unemployment and inflation are sky-high.

"We want the stoppage immediately of their [Iran's] sponsoring of terrorism. They sponsor terrorism at a level that nobody's ever seen before," Trump added.

The new measures come during a spurt of violence in the Persian Gulf and Gulf of Oman. Iran shot down a naval reconnaissance drone in the Gulf of Oman on June 20, while several oil tankers have been attacked in the same area. 

The US has repeatedly accused Iran of launching the attacks – accusations Iran has vehemently denied.

Secretary of State Mike Pompeo warned on Sunday of the new sanctions, stating that their aim was to “deny Iran the resources to foment terror, to build out their nuclear weapons system, to build out their missile program,” before leaving for talks with Saudi Arabia.