From USA Today:

The U.S. military cited incidents of insurgent infighting in a rare public description of a split:

• At least six ranking members of al-Qaeda in Iraq have been assassinated by Sunni insurgents or tribal gunmen in separate incidents since September, Zahner said. The killings are usually in retaliation for al-Qaeda's role in violence, such as the execution of local police officers, he said.

• In Ramadi, in western Iraq, he said, armed clashes have erupted between local Iraqi insurgents and al-Qaeda operatives in recent months. At least one high-ranking al-Qaeda member, Abu Khatab, was recently run out of Ramadi by insurgents loyal to the local tribe.

• Near the Syrian border, members of the Albu Mahal tribe, which attacked U.S. positions as recently as March, have lately been pointing U.S. troops to al-Qaeda hideouts, Zahner said.