Three suicide car bomb attacks against offices in a Kurdish-controlled Iraqi town killed at least 25 people on Sunday, most of them Kurdish forces veterans volunteering to re-enlist, officials said.
The Islamic State jihadist group claimed the attack via affiliated Twitter accounts, saying the three suicide bombers were from Germany, Saudi Arabia and Turkey.
"At 10:30 this morning (0730 GMT), three car bombs struck Qara Tapah," said Mayor Wahab Ahmed, who was lightly wounded in the attack.
Qara Tapah lies close to Jalawla, a key battleground northeast of Baghdad between pro-government forces and IS jihadists.
The mayor said the three car bombs targeted his office, a building used by the Kurds' asayesh internal security service and an office of the Patriotic Union of Kurdistan party.
Ahmed said nearby buildings used by the electricity department and the Kurdish peshmerga forces' veterans affairs bureau were also seriously damaged in the explosions.
A high-ranking security official in the autonomous Kurdish regional government put the death toll at 27 and said most of the dead were peshmerga veterans who had volunteered to return to active duty to fight IS.
"Twenty-four of the victims are peshmerga veterans," the official said, speaking on condition of anonymity because he is not authorised to talk to the press.
"They had come to join the front against IS. There are still victims trapped in the debris," he said.
A local federal army official could confirm 25 deaths.
Twitter accounts affiliated with IS relayed a claim naming the three suicide bombers as Abu Sara al-Almani (German), Abu Mohammed al-Jazrawi (Saudi) and Abu Turab al-Turki (Turkey).
Confessionally and ethnically mixed Diyala province, which borders Iran, has seen intense fighting pitting militants of IS against Iraqi federal troops, and their Kurdish and Shiite militia allies.
In the provincial capital Baquba Sunday, a roadside bomb blast in a busy neighbourhood called Al-Dhabbat killed six civilians, a police captain and a doctor at Baquba hospital said.
It was not immediately clear who the explosion targeted.
Two women and a child were among those killed and several others were among the 10 people also wounded in the blast, the sources said.
A woman was killed and two children wounded when another bomb targeted a policeman's home in Baquba's Shifta neighbourhood, the same sources said.