Iraqi military authorities say there are fierce clashes northeast of Fallujah between the army and Islamic State militants following an ambush Friday that killed a general and staff officers.

Militants launched a complex ambush involving a bulldozer packed with explosives against a convoy, killing 1st Division commander Brig. Gen. Hassan Abbas Toufan and three staff officers in the Nadhem al-Taqseem region south of Lake Tharthar.

Two Iraqi officials said Saturday that troops have been rushed to the area and are now fighting in this rural region dotted with small villages. They spoke on condition of anonymity because they were not authorized to speak to journalists.

In the past weeks, the Iraqi army has been focusing on pushing Islamic State militants out of Anbar province and has been reporting incremental progress.