President Joe Biden has ordered the US military to carry out retaliatory strikes against Iranian-backed militia groups after three US service members were injured in a drone attack in northern Iraq.

The Baghdad government condemned that it killed one Iraqi serviceman and wounded 18 other people, adding that it harmed relations between the two countries.

Adrienne Watson, National Security Council spokesman, said one of the US troops suffered critical injuries in the initial drone strike attack that occurred earlier Monday. 

The Iranian-backed militia Kataib Hezbollah and affiliated groups, under an umbrella of Iranian-backed militants, claimed credit for the attack that utilized a one-way attack drone.

Mr Biden, who is spending Christmas at the presidential retreat at Camp David, Maryland, was alerted about the attack by Jake Sullivan, the White House national security adviser, shortly after it occurred on Monday and ordered the Pentagon and his top national security aides to prepare response options.

Sullivan consulted with Lloyd Austin, his defense secretary. Jon Finer, Mr Biden’s deputy national security adviser, was with the president at Camp David and convened top aides to review options, according to a US official, who was not authorized to comment publicly and requested anonymity.

Within hours, Mr Biden convened his nationals security team for a call in which Austin and Gen CQ Brown, the chairman of the Joint Chiefs of Staff, briefed Mr Biden on the response options. Mr Biden opted to target three locations used by Kataib Hezbollah and affiliated groups, the official said.

The US strikes were carried out at about 4:45 am on Tuesday in Iraq, less than 13 hours after the US personnel were attacked.

“The President places no higher priority than the protection of American personnel serving in harm’s way,” Watson said. “The United States will act at a time and in a manner of our choosing should these attacks continue.”

The latest attack on US troops follows months of escalating threats and actions against American forces in the region since the Oct 7 Hamas attack on Israel that sparked the devastating war in Gaza. 

The US has blamed Iran, which has funded and trained Hamas, for the rising violence by its network of proxy groups across the region, including attacks by Yemen’s Houthis against commercial and military vessels thorough a critical shipping choke point in the Red Sea.

The Biden administration has sought to prevent the Israel-Hamas war from spiraling into a wider regional conflict that either opens up new fronts of Israeli fighting or that draws the US in directly. 

The administration’s measured response – where not every attempt on American troops has been met with a counterattack – has drawn criticism from Republicans.

The US has thousands of troops in Iraq training Iraqi forces and combating remnants of the Islamic State group, and hundreds in Syria, mostly on the counter-IS mission. 

They have come under dozens of attacks, though as yet none fatal, since the war began on Oct 7, with the US attributing responsibility to Iran-backed groups.