U.S. carries out air strikes against Iran-backed militia groups in the Iraq-Syria border region.

U.S. carries out air strikes against Iran-backed militia groups in the Iraq-Syria border region.

U.S. carries out air strikes against Iran-backed militia groups in the Iraq-Syria border region.

U.S. military forces carried out what a Pentagon official called “defensive” airstrikes in Iraq and Syria on Sunday against Iran-backed militia groups that were behind drone attacks on American personnel.

Pentagon Press Secretary John Kirby said in a statement that the airstrikes targeted operational and weapons storage facilities at two locations in Syria and one in Iraq. The facilities were used by at least two militias, Kata’ib Hezbollah and Kata’ib Sayyid al-Shuhada, Kirby said.

The fourteenth brigade of the Popular Mobilization Forces, an umbrella group for a number of Iran-backed militias in Iraq, said four of its fighters were killed in the attack. The fourteenth brigade is made up of Kata’ib Sayyid al-Shuhada members.

Sunday’s airstrikes mark the second such attack against similar facilities in and around Syria under the Biden administration. On Feb. 25, the U.S. military conducted airstrikes against targets in eastern Syria that were also used by Iran-backed militia groups involved in other attacks against U.S. personnel in Iraq, according to the Pentagon. 

The Pentagon spokesman added: “As a matter of international law, the United States acted pursuant to its right of self-defense. The strikes were both necessary to address the threat and appropriately limited in scope.”

The UK-based Syrian Observatory for Human Rights said several more fighters were wounded “in an attack by US warplanes”.Syrian state news agency Sana meanwhile reported that a child had died and at least three other people were wounded.

This is the second round of air strikes President Biden has authorised against Iran-backed militias since taking office in January.  US forces based in Iraq have been targeted several times in recent months by drone attacks. Iran has denied any involvement. About 2,500 US troops are based in the country as part of an international coalition fighting the jihadist Islamic State (IS) group.