The U.S. military on Wednesday said American warplanes struck a weapons storage facility in eastern Syria that officials said was being used by Iran-backed militants responsible for dozens of drone and rocket attacks against American troops in the region over the last three weeks.

It was the second such counterstrike in the past two weeks.

“Today, at President Biden’s direction, U.S. military forces conducted a self-defense strike on a facility in eastern Syria used by Iran’s Islamic Revolutionary Guard Corps (IRGC) and affiliated groups,” Defense Secretary Lloyd Austin said in a statement.

Two F-15 fighters launched precision munitions at a weapons-storage warehouse in Deir el-Zour province, according to U.S. officials.