Shafaq News/ Explosions were heard in a U.S. base near al-Omar oilfield in eastern Deir Ezzor countryside following a drone attack by Iran-backed Iraqi paramilitary groups, the Syrian Observatory for Human Rights (SOHR) revealed on Saturday.

The attack comes two hours after a US cargo plane carrying military reinforcements landed in the base, SOHR said. "However, no casualties were reported."

The attack is the second in less than 24 hours, according to the London-based war watchdog.

U.S. bases in Iraq and Syria have come under almost daily fire by the Islamic Resistance of Iraq, a coalition of Iraqi Shiite factions that banded together last month to confront U.S. forces in rejection of Washington’s support for Israel.

The attacks are launched "in response to the crimes committed by the enemy against our people in Gaza".