The US president insists Washington has played no part in ally Israel's bombing campaign, but also warned Iran his patience is wearing thin as the conflict enters a sixth day.

Israeli warplanes targeted the Iranian capital before dawn Wednesday after the military issued a warning for civilians to leave one district for their safety. 

The Israeli military later said it struck weapons manufacturing sites and a facility used to make centrifuges in Tehran. 

Iran told residents of Tel Aviv to prepare for an attack, with the Islamic Revolutionary Guard Corps claiming its hypersonic Fattah-1 missiles were "repeatedly shaking the shelters" in the commercial hub. 

"The 11th wave of the proud Operation Honest Promise 3 using Fattah-1 missiles" was carried out, the Guards said in a statement broadcast on state television.

Hypersonic missiles travel at more than five times the speed of sound and can manoeuvre mid-flight, making them harder to track and intercept.

Iran also sent a "swarm of drones" towards Israel, where the army said it intercepted two over the Dead Sea area.

World powers have scrambled for an offramp, hoping to prevent the conflict from spiralling into a region-engulfing war. 

In separate phone calls with his Iranian counterpart and US envoy Steve Witkoff on Tuesday night, Egyptian Foreign Minister Badr Abdelatty urged a diplomatic solution. 

Trump fuelled speculation about American intervention when he made a hasty exit from the G7 summit in Canada, where the leaders of the club of wealthy democracies jointly called for a ceasefire.

Back in Washington on Tuesday, Trump demanded the Islamic republic's "unconditional surrender".

He also boasted that the United States could easily assassinate Iran's supreme leader.

"We know exactly where the so-called 'Supreme Leader' is hiding. He is an easy target, but is safe there -- We are not going to take him out (kill!), at least not for now," Trump wrote on his Truth Social platform.

He met with his National Security Council to discuss the conflict, ending after an hour and 20 minutes with no immediate public statement.

While he has repeatedly vowed to avoid wading into the "forever wars" of the Middle East, Trump ordered the USS Nimitz aircraft carrier to the region along with a number of US military aircraft.

US officials stressed he has not yet made a decision about any intervention. 

The US is deploying more fighter aircraft to the Middle East and extending the deployment of other warplanes, three US officials told Reuters. The US has so far only taken indirect actions in the current conflict with Iran, including helping to shoot down missiles fired toward Israel.

A source with access to US intelligence reports said Iran has moved some ballistic missile launchers, but it is difficult to determine if they were targeting US forces or Israel.

However, Britain's leader Keir Starmer, speaking at the Group of Seven nations summit in Canada that Trump left early, said there was no indication the US was about to enter the conflict.

The Israeli military said two barrages of Iranian missiles were launched toward Israel in the first two hours of Wednesday morning. Explosions were heard over Tel Aviv. 

Israel told residents in a southwestern area of Tehran to evacuate so its air force could strike Iranian military installations. Iranian news websites said Israel was attacking a university linked to Iran's Revolutionary Guards in the east of the capital.