Iranian cleric Mohammad Ali Movahedi-Kermani told a sermon in Tehran that the Islamic republic is ready for war with the US.
He said: “Think of an attack only if you want to change the color of the Persian Gulf waters from azure to red.”
And he repeated warnings that Iran is ready to abandon all constraints on its nuclear programme imposed by the West.
Imam Movahedi-Kermani also challenged Donald Trump saying he “saw the corpses of US troops before your eyes”.
Trump had claimed he was ready to strike Iran, but backed down at the last minute after a US drone was shot down.
His threats came on Friday as this weekend Iran confirmed it is raising its enrichment of uranium beyond the limit set by the nuclear deal in 2015.
Imam Movahedi-Kermani told Trump: “You saw the corpses of US troops before your eyes, and told yourself they have hit the drone that was flying 65,000 feet above the sea.
“What will they do to a ship that is just in front of them?”
He also threatened to blow up Israel’s nuclear reactor in Negev.
Israel is the US’s closest ally in the Middle East, and Iran has repeatedly threatened to attack them – refusing to recognise them as a state.
Imam Movahedi-Kermani is an influential figure in the regime, having previously been an advisor of Ayatollah Ruhollah Khomeini.
He was also the Ayatollah’s his representative to the powerful Revolutionary Guard.
The cleric however rubbished claims that Iran’s uranium enrichment is for nuclear weapons.
He said: “Iran will continue enrichment to generate electricity and conduct scientific research.”
Iran boasted today it would further scale back its commitment to the 2015 nuclear deal with world powers.
It pledged to raise its uranium enrichment beyond agreed levels to produce fuel for power plants.
The cap is one of many restrictions imposed by the deal that were aimed at extending the time Iran would need to produce a nuclear bomb, if it chose to, to a year from roughly two to three months.
The United States and the UN nuclear watchdog believe Iran had a nuclear weapons programme that it abandoned. Tehran denies ever having had one.
Tensions between Iran and the West have been rising since Trump decided to pull the US out of the nuclear deal in 2018.
US officials accused Iran of plotting attacks on their forces , rushing warships, bombers and troops to the region in the Middle East.
It was then there was a string of attacks on tankers, which was blamed on Iran despite their denials.
Iran then openly admitted shooting down a US drone, a move which almost sparked retribution by Trump before an eleventh hour u-turn.
It emerged today the US allegedly sent a message to Iran warning of an impending limited strike against them.
Revolutionary Guard commander Gholamreza Jalali said they hit back and warned the US if they attacked it would be a declaration of war.
Britain was drawn further into the row this week after the Royal Marines seized an Iranian tanker near Gibraltar suspected of breaching sanctions.
Iran has threatened to seize British ships in response, sparking fears of a new tanker war in the Gulf.