Iraqi military forces have launched an offensive to retake the city of Ramadi from Islamic State militants, U.S. officials said Thursday.

The operation appears to have begun late Wednesday, with Iraqi troops — backed by American and coalition warplanes — first securing the Palestine Bridge, according to information released by the U.S.-led joint task force overseeing the war on ISIS, as the terror group is also known. Located northwest of the city, the bridge is an important supply line that crosses the Euphrates River.

It's not immediately clear if any American ground troops are supporting the operation, or how large the Iraqi military force is. Military Times has submitted those questions to the Combined Joint Task Force - Operation Inherent Resolve, and officials indicated they intend to provide answers.

From the air, unspecified coalition aircraft launched at least seven strikes near the city, which fell to the Islamic State group in May after under-equipped Iraqi soldiers abandoned their posts.

As Iraqi troops began to encircle Ramadi on Wednesday, warplanes targeted what U.S. officials described as five ISIS tactical units. They destroyed a sniper position, two "heavy machine guns" and several other weapons, including homemade explosives, officials said.

Throughout Iraq, coalition aircraft conducted 23 strikes on Wednesday using bombers, fighters, ground-attack jets and drones, officials said. Separate operations are targeting ISIS positions near Beiji, Fallujah, Kisik, Makhmur, Mosul, Qayyarah, Sinjar, Sultan Abdallah and Tal Afar.

Ramadi, the capital of Anbar province, was the scene of tremendous violence during the United States' eight-year occupation of Iraq. More than 70 American troops died as a result of the 2006 campaign to defeat the insurgency there. Veterans of that campaign reacted bitterly to news of city's fall to ISIS earlier this year.

Last month, U.S. officials indicated the Iraq's army — after months of training by American soldiers and Marines — were ready to retake the city. The Iraqi government announced plans for the operation in July.

There are approximately 3,500 American troops in Iraq working to train and advise the Iraqi military. Apart from select missions involving special forces elements, they are not participating in direct ground combat. Since the summer, the Army also has launched several hundred artillery strikes on ISIS targets in Iraq, a development noted this week by the Washington Post.