President Joe Biden has directed airstrikes on Iran-backed militia groups in the Iraq-Syria border region in response to unmanned aerial vehicle attacks.

Pentagon press secretary John Kirby said in a statement

Sunday that U.S. military forces conducted the “defensive precision airstrikes” against facilities used by Iran-backed militia groups in the region on Sunday evening. Kirby, who stressed the U.S. strikes were legal and in self-defense, said, “the targets were selected because these facilities are utilized by Iran-backed militias that are engaged in unmanned aerial vehicle (UAV) attacks against U.S. personnel and facilities in Iraq. Specifically, the U.S. strikes targeted operational and weapons storage facilities at two locations in Syria and one location in Iraq, both of which lie close to the border between those countries. Several Iran-backed militia groups, including Kata’ib Hezbollah (KH) and Kata’ib Sayyid al-Shuhada (KSS), used these facilities.”

The airstrikes come at a time of heightened tension between the U.S. and Iran, as the two nations hold talks on returning Tehran to the 2015 nuclear deal. Biden declined to comment to reporters on the latest airstrikes after returning to the White House Sunday evening from a weekend at Camp David, telling reporters: “I’ll talk to you tomorrow.”