US Vice-President J.D. Vance said on Tuesday that diplomatic talks between Washington and Tehran had made “good progress”, but warned that the US military was “locked and loaded” to restart its campaign against Iran if negotiations collapsed.

“A lot of good progress is being made, but we’re just going to keep on working at it, and eventually we’ll either hit a deal or we won’t,” Vance said during a White House press briefing.

“We are not going to have a deal that allows the Iranians to have a nuclear weapon, so as the president just told me, we are locked and loaded,” he said, adding: “We don’t want to go down that pathway, but the president is willing and able to if we have to.”

With the fragile ceasefire between the two sides under strain, US President Donald Trump has repeatedly threatened to strike Iran, warning that the April truce could collapse if Tehran does not reach a deal, and he has continued to adjust the conditions for one.

Vance spoke hours after Trump told reporters he had given Tehran “two or three days” to reach an agreement. “I was an hour away from making the decision to go today,” Trump said on Tuesday.

On Monday, Trump said he had called off strikes on Iran planned for Tuesday at the urging of Gulf leaders, as “serious negotiations” for a deal to end the war were underway.