U.S. President Joe Biden ordered strikes on two facilities in Syria following attacks on U.S. troops in the past week, the Pentagon said, warning the U.S. will take additional measures if attacks by Iran's proxies continue.

U.S. forces have been hit more than a dozen times in Iraq and Syria in the past week by what Washington suspects are Iran-backed groups. Hamas, Islamic Jihad and Lebanon's Hezbollah are all backed by Tehran.

Iranian Foreign Minister Hossein Amirabdollahian said at the United Nations on Thursday that if Israel's offensive against Hamas did not stop, the United States will "not be spared from this fire."