Iran's President Hasan Rouhani accused the Trump White House of being "afflicted with mental retardation" in a TV address on Tuesday.

Rouhani said that new sanctions, targeted at Iran's Supreme Leader, show that the US is not serious about finding a diplomatic end to their current conflict.

The US on Monday imposed new sanctions on Iranian officials, including Supreme Leader Ayatollah Ali Khamenei.

In recent weeks tensions between Iran and the US have surged. Iran shot down a US drone, and President Donald Trump almost responded with military action.

Visit Business Insider's homepage for more stories.

Iran's President Hassan Rouhani has accused the administration of President Donald Trump of being "afflicted with mental retardation" in an inflammatory TV address on Tuesday.

It came after the US imposed sanctions targeted at the country's supreme leader, Ayatollah Ali Khamenei.

Speaking in a live address Tuesday, translated and reported by The Associated Press, Rouhani also said that the sanctions will lead to the "certain failure" of US policy.

"How can a person lose their mind so badly and do something so outrageous and idiotic by sanctioning the leader of a country?" said Rouhani, according to a translation by Sky.

"They are suffering from mental disability. The White House is afflicted by mental retardation and does not know what to do."

A screengrab from Sky News shows Rouhani mocking the Trump White House. Sky News

He also criticised plans by the US to sanction Iranian Foreign Minister Mohammad Javad Zarif later this week.

He said the move showed that US claims to be seeking a diplomatic solution to the crisis were not serious.

"You sanction the foreign minister simultaneously with a request for talks?" he said, highlighting an apparent contradiction in the US approach.

In a tweet, Zarif echoed the criticism.

"But it's now clear that the # B_Team is not concerned with US interests—they despise diplomacy, and thirst for war," tweeted the foreign minister.

Iranian officials have previously described hawkish aides around Trump as the "B Team."

The sanctions come after weeks of escalating tensions between the US and Iran.

Trump said he at the last minute reversed a decision last week to launch airstrikes against Iran in retaliation for the downing of a US drone.

In an interview with NBC News, broadcast Sunday, the president held out the offer of talks with Iran's leader with no preconditions.