Two bomb attacks claimed by a radical Kurdish group hit Istanbul over the past week, killing one and injuring several others, as deadly Kurdish riots flared in the southeast.

Acting on intelligence that more violence is being planned, police raided a house in the distant Istanbul suburb of Kucukcekmece, detaining two suspected members of the outlawed Kurdistan Workers' Party (PKK) and seizing 3.8 kilos (8.4 lbs) of plastic explosives, officials told Anatolia.

Nine other suspects were detained in separate raids in the city, which the seizure of a further four kilos (8.8 lbs) of explosives.

The Kurdistan Freedom Falcons (TAK), believed to be a cover for the PKK's urban attacks, on Wednesday claimed responsibility for an explosion that wounded three at an office here of the ruling Justice and Development Party.

On March 31, the group took the blame for a bomb blast that killed one and wounded 13 at a bus station in the city.

TAK has threatened to carry out more attacks as a reprisal for the killing of 12 people during a week of Kurdish riots in the southeast.

The unrest, which erupted on March 28, spilled over to Istanbul, where three women were crushed to death when a firebomb hurled by Kurdish protestors set a city bus ablaze and sent it crashing into another vehicle.

The Kurdish conflict in Turkey has claimed more than 37,000 lives since 1984 when the PKK, considered a terrorist group by Ankara, the European Union and the United States, took up arms for Kurdish self-rule in the southeast.