BEIRUT >> A rocket attack Monday targeted a base in eastern Syria where U.S. troops are based causing no injuries or damage, the U.S. military said.

The military said in a statement that one rocket struck the Mission Support Site Conoco in eastern Syria on Monday evening and another rocket was found at the attack point of origin.

No one claimed responsibility for the attack.

The Britain-based Syrian Observatory for Human Rights, an opposition war monitor, said that Iran-backed fighters based in eastern Syria might have been behind the attack.

In late March, U.S. forces retaliated with airstrikes on sites in Syria used by groups affiliated with Iran’s Revolutionary Guard. They followed a suspected Iran-linked drone attack that killed a U.S. contractor and wounded six other Americans in northeast Syria. An official with an Iran-backed group in Iraq said the U.S. strikes killed seven Iranians.

On any given day there are at least 900 U.S. forces in Syria, along with an undisclosed number of contractors. U.S. special operations forces also move in and out of the country, but are usually in small teams and are not included in the official count.

The American troops are trying to prevent any comeback by the Islamic State group, which swept through Iraq and Syria in 2014, taking control of large swaths of territory. The extremists were defeat in Syria in 2019.