Iran has launched "multiple" ballistic missiles in an "attempted surprise attack" on American forces in the Middle East, the US military says, shattering a lull in the fighting.

The attack occurred at 17:45 EDT (21:45 GMT) on Tuesday, and all missiles were "successfully intercepted", said US Central Command, without specifying the locations of any targets.

Tehran has not yet commented. The alleged assault occurred during a break in hostilities between the two countries, which was designed to bring negotiators back to the table.

US President Donald Trump spoke on Monday of "very friendly negotiations" with Iran, after the two sides had not exchanged strikes for a third straight day.

"I think there's a good chance that something could happen," Trump added.

But he had also cautioned that the US could "go back to doing what we were doing" before the break in hostilities.

Access and control of the Strait of Hormuz remains a key sticking point in the talks.

The strikes coincided with Israeli Prime Minister Benjamin Netanyahu's visit to Washington, where he met Trump at the White House and attended the funeral of US Senator Lindsey Graham, a prominent Iran hawk.

Also on Tuesday, Saudi Arabian Defence Ministry spokesman Major General Turki Al-Maliki said their military had intercepted and destroyed several drones targeting patroleum facilities in the country's eastern region.

The statement alleged the drones were launched from Iraqi territory, and were perpetrated by Iran-affiliated militia groups.

At least 624 US military service members have been wounded since Trump ordered strikes against Iran in February, according to recent Pentagon data.

The Pentagon said 417 of those personnel were injured in relation to Operation Epic Fury, the joint US-Israeli military operation against Iran.