Baghdad's Arab-led central government and the Kurdistan region are embroiled in a long-running dispute over oil and land and both dispatched troops last month to the so-called "Disputed Territories" over which both claim jurisdiction.
No one claimed responsibility for Sunday's bombing in the ethnically mixed town of Jalawla, 115 km (70 miles), north-east of Baghdad, near a Patriotic Union of Kurdistan party (PUK) office when Kurds were being recruited into Peshmerga forces. "We were waiting to be recruited in the Peshmerga and then there was a big sound of an explosion and a shock wave," said Cerwan Mohammed Ameen, 26, one of 12 wounded by the blast.
"I woke up later to find myself in the hospital and I saw my friends near me," said Ameen, who had burn wounds on his legs. The military build-up, the second major troop escalation inside Iraq since US troops left a year ago, threatens to ignite tensions in the disputed areas and risks fracturing the country's fragile federal unity.