No casualties were reported in the three attacks, part of a series that began on Monday, the anniversary of a U.S. airstrike that killed top Iranian general Qassim Soleimani in Baghdad two years ago.
According to an Iraqi officer, an Iraqi base housing U.S. troops in the western Anbar province was hit with five Katyusha rockets on Wednesday evening; three other rockets fell outside the base's parameter. The officer, who spoke on condition of anonymity in line with regulations, said U.S.-led coalition forces at the base were forced into shelters by the barrage.
There was no immediate comment from the coalition, which is in Iraq to help fight the Islamic State group.
Later Wednesday, a previously-unheard of group in Iraq calling itself Qassem al-Jabarayn claimed responsibility for the Ain al-Asad attack. The group vowed in an online post to keep up attacks until the full withdrawal of U.S. forces.
Since Soleimani’s death, Iran-backed militias in Iraq have become increasingly unruly and disparate, although some analysts argue the militias have splintered only to allow them to claim attacks under different names to mask their involvement.
Earlier Wednesday, the Iraqi military said a rocket launcher with one rocket was located in a residential district in western Baghdad, an area used in the past by Iran-backed militias to fire at the airport.
In eastern Syria, the rounds hit a base run by the U.S.-backed Syrian Democratic Forces with a small coalition advisory presence. The coalition said in a statement there was minor damage.
Coalition forces, acting on intelligence, responded by firing six rounds of artillery towards the point of origin of the attack just outside the eastern town of Mayadeen, a stronghold of Iran-backed fighters, the statement said.
The statement said “Iran-supported malign actors fired ... from within civilian infrastructure with no regard for civilian safety.” It said that hours earlier, U.S.-led coalition forces had observed several launch sites near the base known as Green Village. Coalition forces conducted several strikes to eliminate the threats, it added.
“The Coalition reserves the right to defend itself and partner forces against any threat, and will continue to do everything within its power to protect those forces,” said Maj. Gen. John W. Brennan, Jr., commander of the joint task force.
John Kirby, Pentagon press secretary, said Wednesday that the military has been preparing for stepped-up attacks in Iraq around the end of the year.
“We’re very mindful of the threat environment and it is very dynamic right now,” he said. Kirby said the attacks could be related to the anniversary of Soleimani's killing or a reaction to the continuing presence of American forces in Iraq — but likely are a combination of both.
Iranian-backed militias have wanted all U.S. troops out of the country, and many believed that would happen by the end of the year.
On Monday, two armed drones were shot down as they headed toward a facility housing U.S. advisors at Baghdad airport. Two explosives-laden drones targeting an Iraqi military base housing U.S. troops in western Anbar province were destroyed on Tuesday.
The 2020 U.S. drone strike at Baghdad’s airport killed Soleimani, who was the head of Iran’s elite Quds Force, and Abu Mahdi al-Muhandis, deputy commander of Iran-backed militias in Iraq known as the Popular Mobilization Forces.
Pro-Iran Shiite factions in Iraq have vowed revenge for the killing and have conditioned the end of attacks against the U.S. presence in Iraq on the full exit of American troops from the country.
The U.S.-led coalition formally ended its combat mission supporting Iraqi forces in the ongoing fight against the Islamic State group last month. Some 2,500 troops will remain as the coalition shifts to an advisory mission to continue supporting Iraqi forces.
The top U.S. commander for the Middle East Marine Gen. Frank McKenzie warned in an interview with The Associated Press last month that he expects increasing attacks on U.S. and Iraqi personnel by Iranian-backed militias determined to get American forces out.
Associated Press writers Bassem Mroue in Beirut and Lolita Baldor in Washington contributed to this report.