VIDEO | US and Iran trade blows again, Strait of Hormuz control at centre of dispute

In a brief phone interview with Reuters on Sunday, US President Donald Trump referred to the weekend's strikes on Iran. "We're beating them up," he said.

Trump has said he considers the ceasefire over, while leaving the door open to further talks.

Iran's top negotiator, Mohammad Baqer Qalibaf, struck a similarly defiant tone, posting on social media on Sunday: "The era of one-sided deals is OVER. We told you: keep your word or pay the price. Reality is knocking."

The war launched by the United States and Israel against Iran on February 28 has destabilised the gulf, and spread across the region, with Iran attacking US bases in multiple countries. Thousands of people have been killed, mainly in Iran and Lebanon.

Tehran's effective blockade of the Strait of Hormuz has driven energy prices higher and fuelled inflation concerns worldwide.