Biden’s notification on Saturday is a routine part of the War Powers Act, which requires the president to notify Congress within 48 hours of military actions.

United States President Joe Biden on Saturday informed Congress of his decision to approve an airstrike in Syria last week against what Washington said were Iranian-affiliated facilities.

The US airstrike came after a drone attack by a suspected Iranian-backed group struck a base housing US personnel in northeastern Syria, leaving an American contractor dead and wounding five US service members.

Biden said in his letter to Congress that the strikes were made “in order to protect and defend the safety of our personnel, to degrade and disrupt the ongoing series of attacks against the United States and our partners, and to deter the Islamic Republic of Iran and Iran backed militia groups from conducting or supporting further attacks on United States personnel and facilities.”

The president, who had vowed that the US will “forcefully protect our people” after authorising the retaliatory airstrike in response to the Iranian drone attack, also added that the US strikes “were conducted in a manner intended to establish deterrence, limit the risk of escalation, and avoid civilian casualties”.

Biden’s notification on Saturday is a routine part of the War Powers Act, which requires the president to notify Congress within 48 hours of military actions. The letter was sent to both House Speaker Kevin McCarthy and President Pro Tempore of the Senate Sen. Patty Murray.

The strikes are likely to increase tensions with Iran, with which the proxy groups are aligned, though Tehran isn’t always involved in directing attacks that they conduct.

The US has already sanctioned the country for providing attack drones to Russia to use in the war in Ukraine. Chairman of the Joint Chiefs of Staff Gen. Mark Milley on Thursday reiterated US concerns that Iran has the potential to produce enough fissile material for a nuclear weapon in less than two weeks and manufacture one within months.

Pentagon spokesman Brig. Gen. Patrick Ryder on Friday emphasised to reporters that the US is not seeking conflict with Iran, but said the strikes “were intended to send a very clear message that we will take the protection of our personnel seriously and that we will respond quickly and decisively if they’re threatened”.