Efforts to end the Iran conflict were at an impasse on Tuesday (Apr 28) with US President Donald Trump unhappy with the latest proposal from Tehran, which he said had informed the US it was in a "state of collapse" and was figuring out its leadership situation.

Iran's most recent offer for resolving the two-month war would set aside discussion of its nuclear programme until the conflict was concluded and shipping disputes resolved.

But Trump wants nuclear issues dealt with from the outset, a US official briefed on Trump's Monday meeting with his advisers said.

In a Truth Social post on Tuesday, Trump said: "Iran has just informed us that they are in a 'State of Collapse'. They want us to 'Open the Hormuz Strait,' as soon as possible, as they try to figure out their leadership situation (Which I believe they will be able to do!)."

It was unclear from his post how Iran might have communicated that message and there was no immediate response from Tehran to Trump's latest comments.

Earlier, an Iranian army spokesperson told state media the Islamic Republic did not consider the war over.

Iran has largely blocked all shipping apart from its own from the Gulf through the Strait of Hormuz, a chokepoint for global energy supplies, since the war began on Feb 28. This month, the US began blockading Iranian ships.

The Wall Street Journal reported, citing US officials, that the president had instructed aides to prepare for an extended blockade of Iran's ports.