Turkish warplanes have bombed a Kurdish Worker's party (PKK) rebel base in northern Iraq, killing an unspecified number of militants.

The "intensive" bombing targeted a large cave in the Qandil mountains, where up to 40 PKK militants taking refugee, the military said in a statement on Tuesday.

"The cave was completely destroyed and most of the militants who were inside and outside the cave were rendered ineffective," the army statement added.

Turkish fighter jets also struck other targets in Zap area along the Turkish border. The statement, however gave no further details.

The raids followed a double bomb attack in Istanbul on Sunday night in which 17 people were killed and over 150 wounded.

Turkish authorities blamed PKK insurgents for the bombings; PKK however denies any involvement in the attacks.

The PKK launched an insurgency nearly three decades ago to separate the mainly Kurdish provinces of Turkey in the east and south. The battle between the militants and Turkish Military has so far left 37,000 people killed.

SB/DT