Incoming missile sirens sounded early in the morning in Dubai in the United Arab Emirates and Bahrain, while Saudi Arabia said it had destroyed two drones over its oil-rich eastern region and Kuwait's National Guard said it had show down six drones.

In addition to firing missiles and drones at Israel and American bases in the region, Iran has also been targeting energy infrastructure which, combined with its stranglehold on the Strait of Hormuz, has sent oil prices soaring.

Brent crude, the international standard, spiked to nearly USD 120 on Monday before falling back but was still at around USD 90 a barrel on Tuesday, nearly 24 per cent higher than when the war started on Feb 28.

US President Donald Trump, who has previously said that the war could last for a month or longer, on Tuesday sought to downplay growing fears that it could be a long-term regional conflict, saying it was "going to be a short-term excursion."

The war has choked off major supplies of oil and gas to world markets and sent fuel prices rising across the US. The fighting has also led foreigners to flee from business hubs and prompted millions to seek shelter as bombs hit military bases, government buildings, oil and water installations, hotels and at least one school.