Iraqi forces broke the Islamic State group's siege of the country's largest oil refinery in the northern town of Baiji Saturday, after jihadists had control of it for months.

Three military officers confirmed that Iraqi forces had reached the refinery just 120 miles north of Baghdad. Since June, security forces have been under attack and surrounded in the area.

A day before, the pro-government groups re-took a town nearby Baiji, making it the largest town to be retaken since IS-led militants swept across Iraq's Sunni Arab heartland.

Earlier in the week, the army and Shiite militiamen took back control of one of the country's largest Dams. The Adhaim Dam was seized in the eastern province of Diyala during the joint operation.

America's top officer, chairman of the Joint Chiefs of Staff General Martin Dempsey, flew to Iraq to discuss the growing war against the jihadists.

"The primary purpose of his visit is to get a first-hand look at the situation in Iraq, receive briefings and get a better sense of how the campaign is progressing," Dempsey's spokesman, Colonel Ed Thomas, said.

America is leading a coalition to carry out a campaign of air strikes targeting the IS jihadists in Iraq and Syria.

The United States and other governments have pledged trainers and advisers to aid Iraqi security forces in their battle against the Islamic State.

Rumors said that the Islamic State's leader Abu Bakr al-Baghdadi may have been wounded or killed by the coalition air strikes. An audio tape released by the group cannot confirm if the allegations are true.

The plan to retake Baiji started over a month ago but security forces were slowed by bombs planted by militants.

Security forces and pro-government fighters advanced towards the town from the south and gained access by Oct. 31.

The oil refinery in Baiji once produced nearly 300,000 barrels a day, accounting for half of the nation's needs in refined oil products.