WASHINGTON -- Many Republicans in Congress swiftly rallied behind US President Donald Trump after he had ordered strikes on three Iranian nuclear sites on Saturday, while senior Democrats condemned it as an unconstitutional move.

Leading Republicans in Congress, House Speaker Mike Johnson and Senate Majority Leader John Thune, commended the military operation in separate statements, calling it a necessary check on Iran's ambitions of developing a nuclear weapon.

However, leading Democrats, who only received notifications shortly before Trump's public announcement of the strikes, harshly criticized the move.

US House Minority Leader Hakeem Jeffries blasted Trump's action, saying he "failed to seek congressional authorization for the use of military force and risks American entanglement in a potentially disastrous war in the Middle East."

He said in a statement that the president "shoulders complete and total responsibility for any adverse consequences that flow from his unilateral military action."

In a statement, Senate Democratic Leader Chuck Schumer demanded "clear answers" from Trump regarding the operation and called for enforcing the War Powers Act, legislation that limits the president's power to unilaterally sign off on prolonged military entanglements abroad without authorization from Congress.