US President Donald Trump on Tuesday accused Iran of having repeatedly violated a temporary truce due to expire soon, with new peace talks mired in doubt after Tehran said it had not yet sent a delegation.

The US leader also touted Washington's strong negotiating position, even as uncertainty grew over a push to stop open conflict from resuming, with the two-week ceasefire set to end by Wednesday.

"Iran has Violated the Cease Fire numerous times!" Trump said in a post on his Truth Social platform, without elaborating.

A US delegation led by Vice President JD Vance was expected to leave soon for Islamabad, which earlier this month hosted a first round of talks that ended without a deal.

Since those marathon talks, Trump has announced a blockade of Iranian ports, while Tehran has closed the Strait of Hormuz again, refusing to send officials for a new round of negotiations that were initially expected on Monday.

"So far, no delegation from Iran has departed for Islamabad, Pakistan," Iranian state TV said on Tuesday, dismissing reports suggesting otherwise.

Both sides have accused the other of ceasefire breaches, with the US leader saying Iran fired on ships in the crucial trade route it has choked, and Tehran calling the US blockade and its seizure of a ship violations as well.

Despite Tehran so far shunning new talks, Trump expressed confidence he could secure an agreement that favoured Washington.

"We're going to end up with a great deal. I think they have no choice... We're in a very, very strong negotiating position," Trump told broadcaster CNBC on Tuesday.

"Iran can get themselves on a very good footing if they make a deal."

Pakistan, meanwhile, continued its down-to-the wire mediation efforts to get both sides to its capital.

Its foreign minister Ishaq Dar urged the warring parties "to consider extending the ceasefire and to give dialogue and diplomacy a chance," according to a Pakistani foreign ministry statement.

Iranian officials, however, say they feel the Trump administration has not acted in good faith in negotiations and has refused to back down from what they called excessive demands.

Its parliament speaker said the country would not accept talks "under the shadow of threats" from the US leader, and would "show new cards on the battlefield" if the conflict resumed. (AFP)


Edited by Aaron Tam