US and Iranian forces exchanged heavy missile and drone attacks over the weekend and into Monday, with Tehran striking US facilities across the Gulf and saying it had again closed the Strait of Hormuz, sending oil prices higher.Iran's Revolutionary Guards said on Monday they had targeted US military facilities in Bahrain and Kuwait, destroyed radar systems in Oman, and hit fuel tanks and ammunition depots at Prince Hassan Air Base in Jordan in response to US strikes.

The US military said it had struck Iranian air defense systems, coastal radar sites, missile and drone capabilities and small boats on Sunday, using aircraft, naval vessels and drones.

The exchanges were an escalation in the pace and geographic scope of attacks over the past week, casting doubt on an interim US-Iranian agreement signed last month to reopen the strait and end the war after a further 60 days of negotiations.

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.