US President Donald Trump is "impatient" about making progress toward ending the Iran war and has instructed his negotiating team to engage the Iranians in good faith, Vice President JD Vance said on Wednesday.

Speaking at an event in Budapest during his trip to Hungary, Vance said a deal was possible if Iran negotiated sincerely, but cautioned that while some parts of the Iranian system were approaching the talks constructively, others were not. He described the situation as a "fragile truce."

"The President of the United States has told me, and he's told the entire negotiating team, secretary of state, the special envoy Steve Witkoff, he said, go and work in good faith to come to an agreement," Vance said.

He added if the Iranians don’t come to the negotiating table, “they’re going to find out that the President of the United States is not one to mess around.

"He's impatient. He's impatient to make progress. He has told us to negotiate in good faith, and I think if they negotiate in good faith, we will be able to find a deal. But that's a big if, and ultimately, it's up to the Iranians how they negotiate. I hope they make the right decision," Vance said during a visit to Budapest.

Vance said Trump had shown “that we still have clear military, diplomatic, and maybe most importantly we have extraordinary economic leverage”.

“If they’re going to lie, if they’re going to cheat, if they’re trying to prevent even the fragile truce that we’ve set up from taking place, then they’re not going to be happy,” he added.

His remarks came after the United States and Iran have agreed to a two-week ceasefire brokered by Pakistan, potentially halting a six-week-old war that has killed thousands, spread across the Middle East and caused ​unprecedented disruption to the world's energy supplies.

Iran has signalled the conflict is not over, saying it will only consider the war concluded once formal terms are agreed.

Trump announced the agreement late on Tuesday, just two hours before a deadline he had set for Iran to open the blockaded Strait of ‌Hormuz or face the destruction of its "whole civilisation".

In a statement on Wednesday morning, Israeli Prime Minister Benjamin Netanyahu’s office said it supports Trump’s decision to suspend strikes against Iran for two weeks, but that it doesn’t include the war with Hezbollah in Lebanon, where more than 1,500 people have been killed.