Three car bombs, including a suicide attack, killed at least four people on Sunday in disputed territory in northern Iraq where analysts fear tensions could trigger a full-blown conflict.
The unresolved row over the swathe of land, which Iraqi Kurdistan wants to incorporate into it's three-province autonomous region over Baghdad's objections, is cited by diplomats as among the biggest threats to Iraq's long-term stability.
In the town of Riyadh, just west of the ethnically-mixed city of Kirkuk, three policemen were killed and 14 people were wounded when a suicide attacker set off a minibus rigged with explosives outside the town's police headquarters, according to police Brigadier General Sarhad Qader.
Among the wounded in the 10:00 am (0700 GMT) attack were nine policemen, including local police chief Major Mundher Ahmed.
Another person was killed and 27 were wounded by two car bombs targeting Shiite Turkmen areas of Tuz Khurmatu, another ethnically-diverse town in the disputed territory, which stretches from Iraq's eastern border with Iran to its western frontier with Syria.
The row is one of several between the central government and the autonomous Kurdish region, and diplomats and analysts often voice worry that tensions tied to the disputes could spill over into armed conflict.
Iraq has suffered a surge in violence since the beginning of the year, coinciding with rising discontent among Sunnis that erupted into protests in late December.
Analysts say a failure by the Shiite-led authorities to address the underlying causes of the demonstrations has given militant groups both a recruitment platform and room to manoeuvre.