There is a warning today a major spike in oil prices risks slamming the brakes on world economic growth.

Research from AMP chief economist Shayne Oliver shows a $US40 a barrel rise in oil prices could add 40 cents a litre to petrol prices.

He says higher energy prices are effectively a "tax on consumer spending" , and historical data shows them playing a part in the recessions of past global downturns, including the GFC of 2007.

This in turn could contribute to a more volatile sharemarket.

The firing of a Ramadan iftar cannon in Dubai triggered panic among tourists at one hotel.

Footage on social media shows guests leaping from their tables on hearing the cannon firing, while waiters remain calm.

Dubai and other UAE states have been targeted by Iranian drone and missile strikes over past days.

The firing of the iftar cannon at sunset is a Ramadan tradition that marks the time to break the fast.

The Israeli ambassador to the UN says the fighting will last "as long as it takes" to end the threats from Iran.

Danny Danon has just been briefing media, telling them the growing civilian death toll, including Israelis, is part of the "sacrifice" for future generations and it will continue."

He says Israeli objectives are to rid Iran of its nuclear weapons, ballistic missile threat, destroy its navy and dismantle the regime's network of proxy groups.

The Lebanese government says Israeli strikes have left at least 52 people dead and 154 wounded.

Israel said it had carried out attacks against Hezbollah targets in the country after the group launched projectiles at what it said was a military base in northern Israel.

The Israeli Defence Forces says the strikes were targeting branches of al-Qard al-Hasan, a non-profit charity institution operating outside the Lebanese financial system.

Israel has long claimed it was being used to fund the militant group's military wing.

Dubai-based airline Emirates says it will begin operating a limited number of flights starting on Monday evening (Tuesday AEDT) as part of a gradual resumption of services.

The carrier said priority will be given to customers with earlier bookings.

Emirates will contact directly those rebooked to travel on these limited flights.

It also urged passengers not to proceed to the airport unless they have been notified with confirmed flight details.

All other Emirates flights remain suspended until further notice, with the airline monitoring the situation and adjusting its operational schedule accordingly.

A fourth member of the United States armed forces has been confirmed dead.

US Central Command (CENTCOM) says the services member died after being wounded during Iran's initial attacks in response to US and Israeli strikes across Iran on Saturday.

The US Defence Department has not yet disclosed the identities of those killed, pending notifications of their families.

Trump says the US is "already substantially ahead of our time projections" on the war with Iran, but did not offer a definitive answer on when he expects the military operation to conclude.

"Whatever the time is, it's OK. Whatever it takes," Trump said during remarks at the White House.

"Right from the beginning, we projected four to five weeks, but we have capability to go far longer than that. We'll do it."

Trump dismissed the notion that he would get bored after four to five weeks of conflict in Iran.

"They said, 'Oh, well, the president wants to do it really quickly. After that, he'll get bored'. I don't get bored. There's nothing boring about this," Trump said.

The US president returned to the White House overnight, having been at his Mar-a-Largo property in Florida since ordering the first strikes on Iran on Saturday.

In his first in-person and live remarks to reporters since the Saturday, Trump says Iran ignored warnings not to rebuild its nuclear program.

Trump is speaking at an unrelated ceremony at the White House.

"Following our obliteration of Iran's nuclear program and Operation Midnight Hammer a short while ago [June last year], we warned Iran not to make any attempt to rebuild at a different location, because they were unable to use the ones we so powerfully blew up, but they ignored those warnings and refused to cease their pursuit of nuclear weapons," Trump said.

"The regime already had missiles capable of hitting Europe and our bases, both local and overseas, and would soon have had missiles capable of reaching our beautiful America," he added.