The White House has praised the US House of Representatives for rebuffing a bid to halt President Donald Trump's military action in Iran, a day after a similar measure collapsed in the Senate.

The House war powers resolution - rejected ina narrow vote of 219-212 - was largely symbolic and would have been unlikely to survive an expected veto from the president.

Democrats have criticised Trump for launching strikes without congressional approval and questioned whether the US was facing the kind of "imminent" threat that would justify the president ordering strikes on his own.

The US and Israel launched the military action last Saturday and it is unclear how long the conflict could last.

In a statement after Thursday's House vote, the White House said: "Congress has reaffirmed the Commander-in-Chief's Constitutional authority to protect the American people from the Iranian regime's murderous ambitions and imminent threats."

Four Democrats - Jared Golden of Maine, Greg Landsman of Ohio, Henry Cuellar of Texas and Juan Vargas of California - defied their party to help Republicans defeat the war powers resolution.

Two Republicans - Thomas Massie of Kentucky and Warren Davidson of Ohio - crossed the aisle to join Democrats in support of the legislation.

Davidson, an Army veteran, said in a statement: "President Trump's America First message was supposed to be a rejection of the globalist war machine."

If the resolution had cleared Congress it would have stopped US military action in Iran pending deliberation from lawmakers on whether to grant approval.

House Speaker Mike Johnson, who pushed for Congress to vote against the act, praised the outcome, saying that to pass it would have been "a very serious misstep by Congress".

"We are not at war," he argued. "We have no intention of being at war. This is a limited operation."

Democrats in both chambers of Congress have argued that Trump ignored congressional input and has offered vague reasons and objectives for the war, which the White House denies.

Some Republicans in the House and Senate said that while they blocked the resolution for now, they could change course if the war expands or drags on.

On Thursday at the White House, Trump said the US was striking Iranian drone and missile capabilities "every single hour".

"So they have no air force, they have no air defence," he said. "All of their airplanes are gone, their communications are gone."

Trump said Iran was "calling and saying how do we make a deal".

"I say you're being a little bit late," the president said. "We want to fight now more than they do."

While the president has broad authority to launch military action without a formal declaration of war, Congress must by law be notified within 48 hours of hostilities beginning.

Secretary of State Marco Rubio has maintained the Trump administration complied with that requirement.

Speaker Johnson has said the Trump administration notified the so-called gang of eight - a bipartisan group of the top eight congressional leaders - before the strikes.