The United States has cautioned it remains fully capable of restarting military operations against Iran, even as diplomatic efforts to end the conflict continue to stall over competing conditions.

Pentagon chief Pete Hegseth, speaking at a defence summit in Singapore, said Washington could recommence hostilities if necessary, while US Central Command posted that American forces “remain present and vigilant across the region.

“President Trump has set firm red lines for any agreement — including a permanent ban on Iran developing nuclear weapons and the reopening of the Strait of Hormuz. Iran, however, pushed back, with its foreign ministry spokesman saying the Islamic Republic had “said goodbye to the language of ‘must’ 47 years ago.

“Key sticking points remain: Iran is reportedly demanding the immediate release of $12 billion in frozen assets before advancing talks, while Tehran disputes several terms Trump has publicly announced, including the destruction of its enriched uranium stockpile.

Fighting meanwhile continues in Lebanon, where Israeli forces have pushed beyond a river 30 kilometres north of the Israeli frontier.

A ceasefire between Israel and Hezbollah, supposed to have taken effect April 17, has never held, with both sides accusing each other of violations.A fourth round of Israel-Lebanon talks is expected next week in Washington.