The U.S began conducting airstrikes on Iran-backed positions in Iraq and Syria on Friday, according to four Defense Department officials, the first of what officials expect to be multiple rounds of retaliatory actions following the deaths of three U.S. soldiers in Jordan this week.

President Joe Biden ordered the strikes in response to the deadly Iran-backed attack on U.S. forces at Tower 22, a small outpost in northeast Jordan, last Sunday, which the administration attributed to the umbrella group the Islamic Resistance in Iraq.