A suicide bomber struck a Shia funeral northeast of Baghdad Monday, killing at least 24 people, including militia commanders, in an attack claimed by the Islamic State group, officials said.
The blast in Muqdadiyah, which was hit by a wave of revenge attacks on Sunni homes and mosques after a January suicide bombing, also wounded dozens of people.
The bombing targeted a funeral for a well-known Shia member of the Beni Tamim, one of the main tribes in Diyala province, where Muqdadiyah is located.
Sadiq al-Husseini, the head of the Diyala province security committee, said that a commander from Asaib Ahl al-Haq and another from Badr -- two powerful Shiite militias -- were killed in the blast.
The Islamic State militant group claimed the attack in an online statement, saying a suicide bomber who detonated an explosive belt targeted a gathering of militiamen in Muqdadiyah.
It listed the names of some who were allegedly killed.
Suicide bombings are a tactic almost exclusively employed in Iraq by IS, a Sunni extremist group that overran swathes of the country in 2014.
The Muqdadiyah attack came a day after bombings in a Shia area of northern Baghdad killed at least 39 people and wounded at least 76, the deadliest attacks in the capital so far this year.
IS said in an online statement that two of its suicide bombers carried out the Baghdad attacks.
IS also claimed bombings at a cafe in Muqdadiyah that killed at least 20 people and wounded dozens in January, after which revenge attacks targeted Sunni properties in the area.
Human Rights Watch said Shia militiamen abducted and killed civilians in the Muqdadiyah area after the attack, in addition to burning homes and mosques.
The death of militia leaders in the Monday bombing increases the odds of another round of revenge attacks in the area.
Iraq turned to Shia militia forces in 2014 to help counter an IS onslaught that overran large areas north and west of Baghdad, and they have played a key role in halting the jihadist advance and later pushing them back.
But they have also carried out repeated abuses during the conflict that ultimately feed mistrust of the government and are harmful to Baghdad's efforts to reassert and maintain control in recaptured areas.
Diyala province was declared "liberated" from IS in late January 2015, but that has not brought an end to attacks by the militants.