Militias backed by Iran’s Revolutionary Guards force attacked a U.S. military base in southern Syria with drones recently and on the same day.

A different base used by the U.S.-led coalition near Syria’s eastern border with Iraq came under rocket fire.

U.S. officials saw the back-to-back strikes on Aug. 15 as more sophisticated than previous attacks and feared that more were coming.

That set off a string of tit-for-tat attacks this week — including U.S. airstrikes on three consecutive nights against Iran-linked targets in Syria.

They amplified tensions between two powerful adversaries fighting on a foreign battlefield..

The Americans made clear to Iran, through private channels as well as publicly, that they were not trying to escalate hostilities but only sought to protect U.S. interests, said a U.S.

The U.S. military presence — roughly 900 service members — in Syria makes it a potential target of choice for those players looking to vent their grievances with Washington or its close ally, Israel.

Senior U.S. officials said the Aug. 15 attacks on the two U.S. bases in Syria could have been an Iranian attempt to avenge a previous Israeli attack by targeting Israel’s U.S. allies.

The drone attack, on the U.S. base at al-Tanf, near the border in south Syria, came a day after Israel struck military targets in the Syrian provinces of Damascus and Tartus, killing three Syrian soldiers.