BAGHDAD, Apr. 22 (Reuters) - U.S. forces in Iraq and Syria faced two separate rocket and explosive drone attacks in less than 24 hours, Iraqi security sources and U.S. officials told Reuters on Monday, in the first such incidents reported after a near three-month pause.

Two drones were shot down near Ain al-Asad air base that hosts U.S. troops in the western Iraqi province of Anbar out of an abundance of caution, a U.S. official said.

That followed five rockets fired from northern Iraq toward U.S. forces at a base in Rumalyn in remote northeastern Syria on Sunday, according to U.S. and Iraqi officials.

There were no reports of casualties or significant damage from the attacks.
A U.S. defense official, speaking on condition of anonymity, said the rocket attack on Sunday targeted U.S. troops, in what appeared to be the first attack against U.S. troops in Iraq and Syria since Feb. 4.

On Saturday, a massive explosion at a military base in Iraq killed a member of an Iraqi security force that includes Iran-backed groups.

The force commander said it was an attack, while the army said it was investigating and that there were no warplanes in the sky at the time. The U.S. military denied involvement.

Near-daily rocket and drone strikes on U.S. forces began in mid-October. A group of Iran-backed Shi'ite Muslim armed groups known as the Islamic Resistance in Iraq claimed responsibility, citing U.S. backing for Israel's war in Gaza.

The attacks stopped in late January under pressure from Iraqi authorities and Iran, following deadly U.S. retaliatory airstrikes in Iraq, after three U.S. soldiers were killed in a drone strike on a small base on the Iraqi-Jordanian border.

Iraqi Prime Minister Mohammed Shia al-Sudani returned at the weekend from a week-long visit to the United States, where he met President Joe Biden in an effort to turn a new page in U.S.-Iraqi relations despite soaring regional tensions.

The U.S. invaded Iraq in 2003 and toppled strongman leader Saddam Hussein, withdrawing in 2011 before returning in 2014 at the head of an international military coalition at the Baghdad government's request to help fight Islamic State insurgents.

The U.S. has some 2,500 troops in Iraq and 900 in eastern Syria on an advise-and-assist mission.