Seven people were killed in a double bomb attack Tuesday near the headquarters of an Iranian Kurdish opposition party, in a rare assault in Iraq's relatively secure autonomous Kurdish region, a senior security official said.

The blasts hit the town of Koysinjaq about 10:00 pm (1900 GMT), killing five members of the Kurdistan Democratic Party-Iran, a member of the security forces and a child, said Jalal Karim, the Kurdish region's deputy interior minister.

The attack also left people wounded, said Karim, who did not provide a specific figure.

Iraq's Kurdistan region, which has its own government, security forces and flag but is still part of Iraq, has largely been spared the horrific violence that has plagued other parts of the country in the years after 2003.

The Islamic State jihadist group, which Kurdish forces have battled in the north, including as part of the still ongoing operation to recapture Iraq's second city Mosul, is the usual culprit for attacks in the Kurdistan region.

But the fact that the bombings apparently targeted the Iranian party headquarters raises the possibility that another organisation or country may be responsible.

The Kurds are spread across four nearby countries including Iran, where the military crushed a fledgling Kurdish republic in which Iraqi Kurdish leader Massud Barzani was born in 1946.

There are some five million Kurds in Iran, and various Kurdish opposition groups oppose the government in Tehran.

Iraqi Kurdistan houses a range of Kurdish groups, including armed organisations such as Turkey's Kurdistan Workers' Party (PKK), and Iran's Party of Free Life of Kurdistan (PJAK), which those countries periodically target in air and artillery strikes inside Iraqi territory.