A suicide bomber detonated his explosives among a group of pro-government Sunni militiamen near the Iraqi capital Baghdad, killing at least 24 people.
The attacker mingled with the militiamen as they gathered at a military base in the town of Madain, about 14 miles south of Baghdad, to receive their monthly pay packets.
At least 15 of the dead were Sunni militiamen and the rest were soldiers, while 55 others were injured, local police said.
The Sunni militias, known as Sahwa or Awakening Councils, were formed at the height of Iraq’s sectarian fighting in 2006 and 2007, and allied with US troops against al-Qaida in Iraq, a precursor to the Islamic State extremist group.
They are viewed as traitors by Sunni extremists fighting to overthrow the Shiite-led government.
In another attack, four civilians were killed and seven wounded when a bomb tore through an outdoor market in the town of Youssifiyah, 12 miles south of Baghdad, a police officer said.
No-one immediately claimed responsibility for the bombings, but they bore the hallmarks of the Islamic State group, which captured large swaths of western and northern Iraq in a summer blitz.