Iran says new US sanctions will have 'no impact'

The new economic sanctions that the United States is preparing to impose on Iran will have no "impact", a spokesman for the Islamic republic's foreign ministry said Monday.

"We really do not know what (the new sanctions) are and what they want to target anymore, and also do not consider them to have any impact," Abbas Mousavi said at a press conference in Tehran.

"Are there really any sanctions left that the United States has not imposed on our country recently or in the past 40 years?" he added.

Tensions between Washington and Tehran flared after Iranian forces on Thursday shot down a US drone, the latest in a series of incidents including attacks on tankers in sensitive Gulf waters.

US President Donald Trump on Friday called off a planned retaliatory strike at the last minute, tamping down the threat of military action.

He said Washington would instead place "major additional sanctions on Iran on Monday".

Last year, Trump unilaterally pulled the US out of a landmark 2015 deal meant to curb Iran's nuclear programme in exchange for sanctions relief.

The US has since imposed a robust slate of punitive sanctions on Tehran designed to choke off Iranian oil sales and cripple its economy -- which he now plans to expand.

Trump, who has waged a "maximum pressure" campaign against Iran, has also said the US is prepared to negotiate with the Islamic republic with "no preconditions".

"America's claim of readiness for unconditional negotiation is not acceptable with the continuation of threats and sanctions," Hesamodin Ashna, an advisor to Iran's President Hassan Rouhani, said Monday on Twitter.

"We consider war and sanctions to be two sides of the same coin," he added.