An Iranian cleric has mocked the US saying it can't strike back as hard as the late Qassem Soleimani because it only has fictional heroes.

Cleric Shahab Moradi, posted a video to Twitter on Saturday night, a little over a day after the assassination of Islamic Revolutionary Guard Corp Major General Qassem Soleimani.

In the segment the cleric called in to a presenter and said the Islamic Republic would have a hard time taking the revenge that they have promised since the general's death.

Cleric Shahab Mohadi said Iran would find it difficult to respond to Soleimani's death directly because 'All of their [America's] heroes are cartoon characters — they're all fictional'

A file photo dated September 18, 2016 shows Iranian Revolutionary Guards' Quds Force commander Qasem Soleimani during Iranian Supreme Leader Ayatollah Ali Khamenei's meeting with Revolutionary Guards, in Tehran, Iran

He said: '[In the situation] that we take one of theirs now that they've got one of ours — who should we consider to take out in the context of America?

'Think about it. Are we supposed to take out Spider-Man and SpongeBob?

'They don't have any heroes. We have a country in front of us with a large population and a large landmass, but it doesn't have any heroes.

'All of their heroes are cartoon characters — they're all fictional.'

In this photo released by the official website of the Office of the Iranian Supreme Leader, supreme leader Ayatollah Ali Khamenei, front row, fourth from left, leads a prayer over the coffins of Gen. Qassem Soleimani and his comrades, who were killed in Iraq in a U.S. drone strike on Friday, at the Tehran University campus, in Tehran today

A US airstrike late Thursday hit a convoy carrying Soleimani and Iran-backed Kataib-Hezbollah leader Abu Mahdi al-Muhandis near Baghdad airport, shocking the Islamic Republic and sending tensions spiralling across the Middle East.

Soleimani's remains were flown back to Iran last night to a heroes' funeral, with thousands mourning in streets across the country.

Iran has vowed 'severe revenge' against America and yesterday abandoned the remaining limits of its 2015 nuclear deal in response to the airstrike, while Trump has threatened a 'disproportionate response' targeting cultural sites.