Did Trump declare war and did Congress approve Iran attacks? What to know

The Trump administration has warned Iran that "harder hits" are still to come and it was "too late" to talk, as Tehran retaliated with attacks on US and allied targets across the region.

The US and Israel have hit key government sites and the death toll has climbed above 700, including Supreme Leader Ali Khamenei and many senior officials. Israel says it carried out more attacks on Iran's "leadership compound" on Tuesday, including the presidential office.

The US State Department has called on American citizens to leave countries across the Middle East. The US embassies in Riyadh and Kuwait are closing until further notice.

President Trump has said he expects the war to last four to five weeks.

Here's what we know so far:

In his 28 February video announcement, Trump described the US-Israel attacks on Iran as "major combat operations".

As commander in chief, a president can carry out certain military operations without a formal declaration of war.

According to the 1973 War Powers Resolution, the president is required to notify Congress within 48 hours of hostilities beginning.

On Tuesday, Trump submitted a resolution to Congress, telling lawmakers that the threat from Iran had been "untenable" despite efforts to find a diplomatic solution.

Democratic lawmakers and legal scholars have challenged the justification for the strikes and raised concerns about potential violations of the War Powers Resolution.

House Speaker Mike Johnson, a Republican, said the Trump administration had notified the "Gang of 8" - a bipartisan group of the top eight congressional leaders - ahead of the strikes.

The US Congress is set to vote this week on a measure aimed at limiting Trump's ability to wage military operations, which faces significant hurdles. Previous similar attempts during have failed in recent months.

Secretary of State Marco Rubio said on Monday that "it is fine" for Congress to vote, but argued that "there's no law that requires the President to have done anything with regards to this".

"To begin with, no presidential administration has ever accepted the War Powers Act as constitutional - not Republican presidents, not Democratic presidents," he added.

Shortly after explosions were reported in the Iranian capital on 28 February, Trump took to social media to accuse Tehran of waging an "unending campaign of bloodshed and mass murder targeting the United States".

He argued Iran had rejected every opportunity to renounce its nuclear programme and claimed it was developing long-range missiles that could threaten Europe, US troops overseas, and even "soon reach the American homeland".

He further cited the violent takeover of the US embassy in Tehran in 1979, resulting in dozens of Americans being held hostage for 444 days, as well as Iran's proxies bombing a US Marine barracks in Beirut in 1983 that killed 241.

The US president had also pledged in January to intervene when Iranian security forces crushed protests amid an economic crisis.

Trump has also said that it was the "last best chance" to take out missiles and a nuclear threat.

Rubio said on 2 March that the mission's objective is to destroy Iran's ballistic missile and naval capabilities.

He also said the administration knew there was going to be Israeli action against Iran, and the US would have suffered "much higher casualties" from Iran's response if the US had not struck first.

In June last year, the US bombed three nuclear facilities in Iran. Trump said the attack, nicknamed Operation Midnight Hammer by the US, had "obliterated" Iran's nuclear programme.

There's no indication US combat troops will be deployed on the ground in Iran, not least because of the low appetite among the American public for a ground invasion.

"The president has no plan for any kind of large-scale ground force inside of Iran," Republican Senator Tom Cotton told the BBC's US partner CBS on 1 March.

The US operation will include "an extended air and naval campaign", Cotton said, and search-and-rescue efforts could "go in and extract any downed pilot".

The US has about 13 military bases across the Middle East, with 30,000 to 40,000 troops normally deployed between them.

The US military has been building its presence in the Middle East for weeks and has two aircraft carriers, USS Gerald R Ford and USS Abraham Lincoln, in the region.

Trump said on 2 March that the administration expects the campaign to last four to five weeks and that they have "the capability to go far longer than that".

On the same day, Rubio said "the hardest hits are yet to come from the US military" and that the next phase "will be even more punishing on Iran than it is right now".

The US State Department has urged Americans in much of the Middle East to leave via commercial means due to "serious safety risks".

The advisory applies to citizens in Bahrain, Egypt, Iran, Iraq, Israel, the West Bank, Gaza, Jordan, Kuwait, Lebanon, Oman, Qatar, Saudi Arabia, Syria, the United Arab Emirates and Yemen.

Saudi Arabia's Ministry of Defense said on 2 March that the US embassy in Riyadh was attacked by two drones, which caused "a limited fire and minor material damage to the building".

The next day, Rubio confirmed that a drone struck a parking lot near the US consulate in Dubai and that all personnel are accounted for.