United Sates President Donald Trump on Monday ordered “hard-hitting” financial sanctions on Iran’s supreme leader Ayatollah Ali Khamenei, reported AFP. This comes even as Iran downplayed the threat of new US sanctions.

“We will continue to increase pressure on Tehran,” Trump said as he signed the order in the Oval Office, according to AFP. “Never can Iran have a nuclear weapon.”

He held Khamenei “ultimately responsible” for the Islamic republic’s destabilising activities.

On Sunday, United States National Security Advisor John Bolton had warned Iran not to misinterpret Trump’s last-minute cancellation of the planned airstrikes on the country as a sign of weakness. On Friday, Trump had said that he had called off three airstrikes on Iran as 150 people would die.

Trump on Saturday said that the country will impose “major additional sanctions” on Iran from Monday, in a bid to prevent the country from obtaining nuclear weapons. Tehran had warned Washington that it will pay a heavy price if it fires a single bullet.

Tension between both the countries renewed last week after Iran shot down an American spy drone over the Strait of Hormuz. While Tehran claimed the drone violated its airspace, the US maintained it was shot down over international waters. The incident came at a time when the United States accused Iran of attacking two of its oil tankers in the Gulf of Oman on June 13. Hormozgan borders the Strait of Hormuz, where the tankers were located. The US military has also accused Iran of firing a missile at a drone that had responded to the explosions. In May, Washington had alleged Tehran had orchestrated a similar attack in which four tankers in the same area were damaged.

President Donald Trump withdrew from the 2015 Iran nuclear deal and reimposed heavy sanctions on the country. Iran responded to the sanctions by threatening to walk away from its obligations under the nuclear deal – which had promised economic relief in exchange for limits to its nuclear development – and return to higher levels of uranium enrichment.