Iran has warned the US that its aircraft carrier that left the Persian Gulf last week should stay out.

Army chief Ataollah Salehi's warning was the latest and most aggressive statement in the war of words between Tehran and Washington for the control of the strategic Strait of Hormuz.

Iran recently finished naval exercises near the strait and has repeatedly threatened to close the passage, through which 40 per cent of the world's traded crude oil is shipped.

"We recommend to the American warship that passed through the Strait of Hormuz and went to Gulf of Oman not to return to the Persian Gulf," said Salehi. ""The Islamic Republic of Iran will not repeat its warning."

The US dismissed the threat and declined to discuss future movement of the carrier John C Stennis. "The deployment of US military assets in the Persian Gulf region will continue as it has for decades," a Pentagon spokesman said.

"The US Navy operates under international maritime conventions to maintain a constant state of high vigilance to ensure the continued, safe flow of maritime traffic in waterways critical to global commerce."

The US is pushing forward new sanctions against Iran, the world's third-largest oil exporter, over fears about its nuclear programme and President Barack Obama has approved legislation that could penalise buyers of Iranian oil.The European Union has talked of a boycott of crude coming from Teheran.

The Iranian economy has been hit hard by the prospect, with the rial dropping by 40 percent against the dollar in the last month.