ISIS launches attack on Kirkuk

Amman, Jordan (CNN)ISIS militants have launched an attack on the oil-producing northern Iraqi city of Kirkuk.

There had been recent speculation that ISIS might attack Kirkuk to force Kurdish troops to divert their efforts away from Mosul, ISIS' stronghold in Iraq. Peshmerga fighters have moved in around the outskirts of Mosul recently, backed by coalition airstrikes.

ISIS has previously held areas on the outskirts of Kirkuk but not the central city.

Militants took over Maktab Khalid, an area southwest of the city after heavy clashes with Kurdish Peshmerga troops. Among those killed was Brig. Gen. Shirko Fateh, the highest-ranking operational commander of the Peshmerga brigade located in Kirkuk.

Peshmerga fighters continued to battle, attempting to retake the area.

Separately, heavily armed militants attacked an abandoned hotel in central Kirkuk used by local police as headquarters. Police and Peshmerga sources in Kirkuk told CNN that armed men put snipers on the rooftop of the hotel and security forces are surrounding the area.

Peshmerga and Kurdish anti-terror units later raided the hotel, wresting control of it from the militants and killing three of them, Peshmerga sources said. In addition, two suicide bombers detonated themselves in an attempt to keep the Kurdish forces out.