Since the midterm elections on Tuesday, President Donald Trump has alternated between warning Iran of devastating action and insisting a deal is close, leaving allies and adversaries alike unsure what comes next.

Having accepted a heavy Republican defeat, and conceded that the unpopular war with Iran played a part, Trump told reporters on Thursday that the US might have to destroy the rest of Iran and that people would soon find out whether he would. On Friday US forces carried out what he called minor strikes on Iranian air defences, and Iranian state media reported two missiles hitting the Suza area of Qeshm Island in the Strait of Hormuz.

Yet on the same day Trump said his administration was talking to Iranian representatives and had made a lot of progress, adding that Tehran wanted an agreement. He gave no details. On Saturday Qatar's foreign ministry spokesman rejected online claims that the talks had collapsed, saying such rumours serve only those who want the war to drag on.

Qeshm is regarded as a key Iranian naval base, and Washington says it is targeting missile launchers there to stop surface to air missiles being used against US forces. Iran's army said its air defences shot down a US drone over the island, while US Central Command described conditions as relatively calm.

Iran appears to be preparing for something larger. Health officials are reported to be distributing iodine tablets, which shield the thyroid from radiation, to communities within a few kilometres of nuclear facilities, including in the south. One official was quoted as saying Trump could no longer be trusted, and a journalist said officials had been briefed that a US strike on the deeply buried Pickaxe Mountain site was being seriously weighed.

Observers say Iran's tough conditions for reopening Hormuz to shipping, set against Trump's weakened position at home, have left the president with few easy options.