Megyn Kelly once again criticized President Donald Trump's decision to launch strikes on Iran, warning that the conflict could erode his support among women. 

The former Fox News host said polling shows Republicans largely support the president's actions, while independents and Democrats oppose them - and that women in particular are more likely to be against the war.

'What you're seeing now is support falling basically along partisan lines,' Kelly said.

'Republicans, a majority, support the president. Independents and Democrats are totally against the President on this war, which makes some sense. 

'Because, look, I told you guys for the past 20 plus years, I'm a registered Independent. I haven't been a registered Republican in more than two decades, and I'm with the independents.'

Kelly made clear she is siding with voters who are skeptical of the widening conflict.

'As I told you yesterday, most of my Republican audience is supporting the president on it, although a lot aren't,' she continued. 

'Actually, there's an interesting poll showing it's breaking down more severely along gender lines, where a hefty majority of women are against it, and men are split almost 50/50, so that's that's all very interesting, but there is no question that the American people don't understand why we're doing it…'

Her comments came as the war between the United States, Israel and Iran entered its fourth day, with strikes intensifying and retaliation spreading across the region.

US and Israeli forces pummeled targets across Tehran on Tuesday, sending columns of smoke rising over the Iranian capital.

Local media reported strikes on one of the city's two airports and on buildings connected to the committee responsible for selecting a new supreme leader after Ayatollah Ali Khamenei was killed in earlier attacks.

President Donald Trump, who had signaled openness to talks just days before the initial strikes, now appears to be taking a far harder line. 

Posting on social media, Trump wrote: 'Their air defense, air force, navy, and leadership is gone. They want to talk. I said: 'Too late!''

During a meeting with Germany's chancellor in Washington, Trump said that 'most of the people we had in mind' as possible successors to Khamenei were now dead following waves of strikes. 

He also acknowledged the uncertainty that could follow regime change, saying, 'the worst case would be, we do this, and then somebody takes over who's as bad as the previous person'.

Iran has denied seeking talks. Its ambassador to the United Nations in Geneva rejected claims that Tehran approached Washington, even as the country faced mounting damage from coordinated attacks.

The conflict has rapidly expanded beyond Iran's borders.

Iranian drones and missiles targeted US diplomatic sites across the Gulf. A drone strike caused a fire near the US consulate in Dubai. 

Secretary of State Marco Rubio said the strike hit a parking lot and that 'all personnel are accounted for'. 

The US embassy in Riyadh was damaged and briefly caught fire overnight after an Iranian drone strike, while the embassy in Kuwait City was struck earlier in the week, according to diplomatic sources.

Qatar reported intercepting missiles aimed at Hamad International Airport in Doha. Oman said drones targeted the port of Duqm. 

In the United Arab Emirates, falling debris from an intercepted drone caused a fire at an oil storage and trading zone.

Iran's Revolutionary Guards signaled further escalation. General Ebrahim Jabbari warned that if Iran's enemies 'hit our main centres, we will hit all economic centres in the region.' 

Later on Tuesday, the Guards announced 'a large number of missiles' had been fired at Israel.

Israel, for its part, said it had struck an underground facility on the eastern outskirts of Tehran where it claimed Iranian 'scientists operated covertly to develop a key component for nuclear weapons.' 

Israeli forces also moved deeper into southern Lebanon after Hezbollah entered the conflict, firing missiles in support of Tehran. 

Defense Minister Israel Katz said troops had been authorized to 'take control of additional strategic positions in Lebanon in order to prevent attacks on Israeli border communities,' while army chief Eyal Zamir vowed Israel 'will not stop until this organisation is disarmed'.

Inside Tehran, the atmosphere has turned surreal. The capital, normally home to around 10 million people, has emptied out after authorities urged residents to flee.

'There are so few people that you'd think no one ever lived here,' said Samireh, a 33-year-old nurse. Police and security forces have set up checkpoints at major intersections as the bombardment continues.

Global markets have reacted sharply. Energy prices have surged. 

QatarEnergy halted LNG production and announced it would also stop some downstream output, including urea, polymers, methanol and aluminum. 

India warned that disruptions to trade and energy supply chains could have 'serious consequences' for its economy.