Air Delivered event in Deir ez-Zor, Abu Kamal area, Syrian Arab Republic on Fri 27th October 2023

Oct 27 (Reuters) - Two U.S. fighter jets struck weapons and ammunition facilities in Syria on Friday in retaliation for attacks on U.S. forces by Iranian-backed militia as concerns grew that the Israel-Hamas conflict may spread in the Middle East.

U.S. President Joe Biden ordered strikes on the two facilities used by Iran's Revolutionary Guard Corps and militia groups that it backs, the Pentagon said, warning the U.S. will take additional measures if attacks by Iran's proxies continue.

U.S. and coalition troops have been attacked at least 19 times in Iraq and in Syria by Iran-backed forces in the past week. 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".

The U.S. air strikes took place at roughly 4:30 a.m. on Friday (0130 GMT) near Abu Kamal, a Syrian town on the border with Iraq, and were carried out by two F-16 fighter jets using precision munitions, a U.S. defence official said.

"These precision self-defence strikes are a response to a series of ongoing and mostly unsuccessful attacks against U.S. personnel in Iraq and Syria by Iranian-backed militia groups that began on October 17," U.S. Defense Secretary Lloyd Austin said in a statement.

"These Iranian-backed attacks against U.S. forces are unacceptable and must stop," Austin said.

Biden has sent a rare message to Iranian Supreme Leader Ayatollah Ali Khamenei warning Tehran against targeting U.S. personnel in the Middle East, the White House said earlier on Thursday."What we want is for Iran to take very specific actions, to direct its militias and proxies to stand down," a senior U.S. defence official said. The United States did not coordinate the air strikes with Israel, the official added.

The United States has sent warships and fighter aircraft to the region over the last three weeks. On Thursday the Pentagon said about 900 more U.S. troops have arrived in the Middle East or are heading there to bolster air defences for U.S. personnel.

Israel said on Friday military raids into Gaza were preparing "the next stage of the operation", amid fears that a ground invasion of the Palestinian enclave could spark a wider Middle East conflict.

Israel has bombarded the densely populated Gaza Strip following the Oct. 7 Hamas attack on Israeli communities. Israel says Hamas killed some 1,400 people including children, and took more than 200 hostages, some of them infants and older adults.

The Hamas-controlled Gaza health ministry said on Thursday that 7,028 Palestinians had been killed in the retaliatory air strikes, including 2,913 children.

Reuters could not independently verify the tolls.