Two far-leftist groups with alleged links to the Kurdish militant group PKK carried out two bombings in Turkey this week, Interior Minister Suleyman Soylu said on Friday.
A prison guard was killed in an explosion that hit a bus in Turkey's northwestern province of Bursa on Wednesday. A day later, an attacker placed a bomb in Istanbul's Gaziosmanpasa district outside the offices of a non-governmental organization.
"We identified the perpetrators of both attacks, in Bursa and Istanbul. They are affiliated with two organizations subcontracting for the PKK (Kurdistan Workers Party)," Soylu told broadcaster NTV in an interview.
He said the MLKP and the DKP-BOG - groups that are banned in Turkey for alleged links to the PKK had carried out the attacks.
Although attacks have declined sharply in recent years, similar actions have been carried out in the past by Kurdish, leftist and Islamist militants.
On Monday, Turkey announced the start of a new ground and air campaign in northern Iraq, targeting PKK militants.
Dubbed Operation Claw-Lock, Ankara says the offensive is a measure to prevent the PKK from using Iraq as a base to carry out attacks in Turkey.
The PKK is designated as a terrorist organization by Turkey, the United States and the European Union and launched its insurgency for Kurdish self-rule in 1984. More than 40,000 people have been killed in its conflict with the Turkish state.