The tiny island kingdom of Bahrain, home to the headquarters of the US Fifth Fleet, denounced the attacks against its territory and neighbouring Kuwait.

Manama said the two Gulf countries intercepted seven missiles fired by Iran and described the attacks, the second against both nations in three days, as "blatant aggression" and "a flagrant violation of the sovereignty of both countries".

Kuwait also condemned the attacks, saying they were a "direct threat" to the "lives of citizens and residents" and represented a "dangerous escalation... at a time when the international community is making unremitting efforts to stop combat operations".

In the Bahrain capital, an AFP journalist reported hearing three explosions and the interior ministry announced air raid sirens had sounded across the country.

Later, Bahrain's military said in a statement it had been "able to intercept and destroy three missiles and a number of drones".

In Kuwait, an AFP journalist reported hearing repeated blasts near the country's international airport, which had been struck on Wednesday in an attack blamed on Iran that killed one person.

"We woke up to a huge explosion. The explosions were very loud," Reem, an Egyptian mother of two, told AFP, referring to the Saturday attacks.

"My children were terrified, and I couldn't calm them down," she added.

In the hours after the barrages, Kuwait's aviation authority announced the resumption of air traffic, saying 11 Kuwait Airways and Jazeera Airways flights had been diverted during an air space closure due to the Iranian attacks.

Iran's Revolutionary Guards said they had targeted "enemy bases" with missiles after the US military said it struck radar sites in Iran and downed drones headed towards the strategically critical Strait of Hormuz.

US Central Command (CENTCOM) said six of the missiles fired towards Kuwait and Bahrain were downed, while the seventh "did not reach its intended target".

The oil-rich Gulf countries, seen previously as a safe haven in a volatile region, have been in the direct firing line of the war, which began on February 28 with US and Israeli strikes that wiped out Iran's top leadership.

Despite a ceasefire in place since April 8, the Gulf states have been targeted in sporadic attacks during weeks of talks that have failed to secure a deal to permanently end the war and reopen the Strait of Hormuz.