US forces conducted precision strikes Thursday against two facilities used by Iran in eastern Syria, Secretary of Defense Lloyd Austin said in a statement.

Austin said the strikes targeted two facilities used by Iran's Islamic Revolutionary Guard Corps and affiliated groups and were carried out at President Joe Biden's direction.

The strikes were "self-defense" in nature, Austin said, and were meant to retaliate "a series of ongoing and mostly unsuccessful attacks against US personnel in Iraq and Syria by Iranian-backed militia groups that began on October 17."

Due to attacks against US forces, "one US citizen contractor died from a cardiac incident while sheltering in place; 21 US personnel suffered from minor injuries, but all have since returned to duty," he said.