KIRKUK, Iraq (Reuters) - Three suicide bombers attacked Kurdish security forces and the local headquarters of a Kurdish political party in a disputed oil-rich area of northern Iraq on Wednesday, killing three people, police and medics said.
The attacks took place in a band of territory over which both the central government in Baghdad and the Kurds, who run their own administration in the north and are selling oil in defiance of Baghdad, claim jurisdiction.
At the heart of the dispute is the ethnically mixed oil city of Kirkuk, 250 km (155 miles) north of Baghdad.
A suicide bomber in a car attacked the offices of the Patriotic Union of Kurdistan (PUK) in the city, killing one guard, police and hospital sources said.
Another bomber in Kirkuk targeted Kurdish security forces known as peshmerga, killing one, police and medics said. In the town of Tuz Khurmato, about 65 km (40 miles) south of Kirkuk, a suicide bomber in a car killed one peshmerga, security sources said.
No group immediately claimed responsibility.
The Iraqi army and Kurdish peshmerga forces reinforced positions along their contested internal boundary last year, raising the temperature in their long-running feud over land and oil rights.
More Kurdish troops deployed beyond the formal boundary of the Kurdish autonomous region last month, saying they had to protect civilians after clashes between Sunni protesters and Iraqi security forces in Hawija, near Kirkuk.
In the centre of the city of Mosul, also the scene of friction between Kurds and Sunni Arabs, a suicide bomber blew himself up, killing a member of the security forces, police said.
Tensions between Iraq's Sunni Arab, Shi'ite and ethnic Kurdish communities are now at their highest since the withdrawal of U.S. troops in December 2011, with Sunnis in particular growing angrier at what they see as marginalization by Shi'ite Prime Minister Nuri al-Maliki's Baghdad government.
A delicate intercommunal balance has also come under growing strain from the conflict in neighboring Syria, prompting warnings of a return to all-out sectarian conflict.
Although violence is still well below its post-Saddam peak of 2006-07, April was the bloodiest month in Iraq for almost five years, according to the United Nations' Iraq mission.
In the city of Khaniqin, which also lies in the disputed territories, one roadside bomb killed two Iraqi army soldiers and another exploded at the entrance to a mosque, killing a worshipper, police said.
Three people were killed when a bomb attached to a minibus exploded in Taji, 20 km (12 miles) north of Baghdad, police said.
(Reporting by Mustafa Mahmoud and Raheem Salman; Writing by Isabel Coles; Editing by Kevin Liffey)