US Central Command (CENTCOM) is setting up a new task force, called Iron Gate, to stop weapons and sanctioned goods from crossing Iran's land borders and the Caspian Sea, the command said. It will be announced officially later today, Saturday.

The task force will be based at CENTCOM headquarters in Tampa, Florida. It will work with other US government agencies and track arms shipments, dual-use goods and Iran's illegal sources of income. Until now, no details of the group had been made public.

"Stronger cooperation between CENTCOM and our US government partners will further limit Iran's ability to fund terrorism, rebuild weapons factories and restock its military equipment," CENTCOM commander Admiral Brad Cooper said in an official statement.

President Donald Trump imposed the naval blockade in April, soon after the first ceasefire in the war. He lifted it in June as part of a memorandum of understanding, and it was reimposed on 14 July. The US Navy is stopping Iranian oil from reaching world markets to hit Iran's economy even harder.

CENTCOM estimates that the blockade, which has now lasted for months, has stopped more than $25bn of crude oil exports. In August, the US tightened sanctions and dealt a heavy blow to Iran's aviation sector.

In recent weeks, Iran has attacked oil tankers in the Strait of Hormuz several times, while the US is trying to reopen the strait. Tehran says the tankers hit mines.

On Saturday afternoon, Iran's navy reported another tanker that broke the restrictions east of the strait. According to the Iranian account, the ship entered a prohibited and dangerous zone, ignored warnings and kept its navigation systems switched off. It then hit a sea mine, caught fire and was left stuck in place.

Trump said the US struck Iran again overnight, for the first time since Republicans lost the midterm elections. He called the strike "minor".

"They had built a small anti-aircraft site and we destroyed it in about 15 minutes, maybe five," Trump said.

There are also signs of possible progress in talks between Washington and Tehran, with Qatar as the main mediator. Two Middle East sources said on Friday that Iran is looking at Qatari proposals on how to bridge the gaps over its nuclear programme, the hardest issue in the talks.

Tehran will agree to a deal only if Washington accepts 7 conditions, including lifting the naval blockade and sanctions and releasing frozen Iranian funds abroad. One of the sources said Iran does not yet want to negotiate with the Trump administration on the nuclear programme until Washington accepts its main conditions for a truce.

Trump insists the nuclear programme must be part of any deal to end the war, while Tehran says publicly that it will discuss the programme only after the war ends.

A diplomat familiar with the talks said Tehran is ready to discuss nuclear issues it had earlier refused to negotiate. The talks aim to prevent a new military campaign and escalation.