President Donald Trump says the latest strikes by the US hit Iran "very hard", adding that the attacks were "in honour" of three US soldiers killed in recent days - two in Jordan, one in Iraq.

In the early hours of Monday local time, US Central Command (Centcom) said it had launched a "new wave" of strikes for the ninth consecutive night as explosions were heard across Iran.

The US said it had targeted military sites and communications networks to "further diminish" Tehran's attacks on vessels in the Strait of Hormuz.

Iran said it had responded with a "surprise attack" in Syria and targeted US aircraft at Jordan's Aqaba airport.

Elsewhere in the region, Kuwait's armed forces said they had intercepted Iranian drones.

On the US strikes, Iran's semi-official Tasnim news agency reported that several cities had been hit including Tabriz, Chabahar, Konarak, Bandar Mahshahr and Bandar Imam Khomeini.

There were also Iranian state media reports that two oil tankers had exploded as the vessels tried to cross the strait.

The Islamic Revolutionary Guard Corps (IRGC) said the tankers were going through what it called an "unsafe and hazardous southern route" of the strait and "exploded and were brought to a halt". Centcom disputed the claims.

The IRGC added that the strait "will not be safe for the transit of petrochemical products, nor even a single drop of oil and gas" as long as the US strikes continue and that it will respond with a "punitive operation".

Over the weekend, the US confirmed that a service member had been killed after an Iranian attack in northern Iraq on Saturday.

The death came a day after an attack on a base in Jordan where two US soldiers were killed and another was reported missing. The US said "unidentified remains" had been found, with verification of the remains ongoing.

As the strikes continued over the weekend between the US and Iran, US Secretary of State Marco Rubio said that the US "always remains open to a diplomatic solution".

He also said "the world has to decide whether or not it's going to allow an international waterway to be under the control" of Iran, saying Tehran was using the crucial shipping route as leverage.

His comments come as a preliminary deal made in mid-June to stop fighting has unravelled, with negotiations for a permanent peace making little progress after Trump declared the agreement was "over" on 8 July.