Iran urges other countries not to join US sanctions

Iran has condemned the United States' new economic sanctions as "state terrorism" and says other countries are legally obliged not to implement them while the US Treasury Department announced additional targeted Iran-related measures.

The Iranian foreign ministry's statement came as mediators stepped up efforts to reopen the Strait of Hormuz, which handled 20 per cent of world oil supplies before the war began six months ago and whose status remains the biggest obstacle to a peace deal.

US President Donald Trump's administration on Monday warned countries to cut their business ties with Iran or face secondary sanctions although the Treasury Department stopped short of actually imposing penalties.

Trump reiterated on Thursday that the US was not talking with Iran, while the White House said the US economic campaign would continue until Iran decided to "come to the table in a meaningful way".

Iran's foreign ministry said in a statement all countries were obligated under international law to refrain from implementing US sanctions against Iran, adding that participation in them amounted to complicity in imposing one state's unlawful will on independent states.

It branded the new US measures a "crime against humanity" that put the health and livelihood of millions of civilians at serious risk, and called on other countries and United Nations bodies to uphold the rule of law.

Meanwhile, fears of supply shortages led to long queues at petrol stations in Tehran on Friday.

Motorists were waiting at the petrol pumps in the middle of the night, residents said.

At a cabinet meeting this week, President Masoud Pezeshkian acknowledged problems resulting from the war.

Pezeshkian called on the Iranian government itself to exercise restraint with its fleet of vehicles, the ILNA news agency reported.

On Monday, more petrol was sold in Tehran than at any other time this year, the Khabaronline portal reported, citing authorities.

Supreme Leader Ayatollah Mojtaba Khamenei, who was injured and has not been seen publicly since the February 28 attack that killed his father, said in a written statement on Friday that he had banned officials from "committing anything that harms social cohesion".

He urged authorities to avoid any "discouraging statements that weaken national and public motivation," amid concern among Iran's leaders that more financial pressure on its war-battered economy could trigger protests.

Khamenei urged the government to seriously address economic and livelihood challenges including inflation, unemployment, prices and the management of markets for goods and services.