A Sunni faction has killed 18 al-Qaeda militants in an attack on a compound near the Iraqi city of Samarra, police have said.
Another 16 al-Qaeda members were said to have been captured in the attack.
The Sunni Islamic Army of Iraq - once part of the insurgency against US-led forces - said its fighters attacked the compound east of the city.
The faction is one of several Sunni former insurgent groups that have now turned against al-Qaeda.
On Friday, five Sunni Arab tribal leaders had been killed in a suicide attack in Diyala province, north-east of Baghdad.
The BBC's Jim Muir in Baghdad says the Islamic Army of Iraq is apparently planning to use those captured in an exchange of prisoners.
Samarra has been the scene of factional violence
A total of 15 fighters from the Islamic Army were also killed in the attack, police sources told Reuters news agency.
Analysts say that while the Islamic Army shares with the US military a common enemy in al-Qaeda, it does not support the coalition forces or their continued presence in Iraq.
No US or Iraqi security forces are thought to have been involved in the fighting.
Our correspondent says many of the Sunni tribes that used to provide safe havens for the militants are actively combating al-Qaeda.
Much of the violence in the troubled areas north of Baghdad reflect that struggle within the Sunni community, he says.
On Friday, a suicide bomber detonated his explosives belt in the house of Sunni anti-al-Qaeda tribal leader Sheikh Faez al-Obeidi, killing him and four of his relatives.
Those killed were members of the Diyala Salvation Council.
Sheikh Abu Risha, a key US ally in Anbar, was killed in September
Ten others were wounded in the blast, which happened near the town of Khalis.
Diyala province, home to a mixture of Sunnis and Shias, has become a key battleground in the struggle to drive al-Qaeda from Iraq.
The battle has spread there from Anbar province, once a stronghold of the Sunni insurgency.
Many in the Sunni community say they dislike the austere form of Islam that al-Qaeda practises.
The US has provided al-Qaeda's opponents with training and arms.
But al-Qaeda has also carried out a number of attacks on Sunni figures opposed to it.
The leader of the Anbar Awakening, Sheikh Abdul Sattar Abu Risha, was killed in a bomb attack near his home in Ramadi in September.
A senior member of the Salahuddin Awakening Council, Sheikh Muawiya Jebara, was killed by a roadside bomb along with three of his bodyguards in October.
And a Sunni religious leader who encouraged his community to confront al-Qaeda in Iraq, Sheikh Yunis al-Tai, was also killed by a blast at his home in Diyala in August.