Turkish prime minister Ahmet Davutoglu has branded two explosions which killed two people at a Kurdish party rally just days before key parliamentary elections as acts of sabotage and provocation.
"A dirty hand is involved, this dirty hand has to be exposed," Mr Davutoglu said.
Turkey holds parliamentary elections on Sunday in which the Kurdish votes will be crucial in determining whether the ruling party gets the super-majority it seeks.
The ruling AKP party wants a large majority that would allow it to change Turkey's constitution and transfer the prime minister's executive powers to president Recep Tayyip Erdogan in a new presidential system.
If the Kurdish party gets a minimum 10% of the votes required to take seats in parliament, it would effectively block that possibility.
Officials have not confirmed whether the blasts at the People's Democratic Party (HDP) rally in the mainly Kurdish city of Diyarbakir was caused by bombs.
The private Dogan news agency, without citing sources, said one of the explosions was caused by explosives placed in a gas cylinder and fortified with pieces of metal.
"The investigation is continuing but it is clear that it is sabotage, a provocation and an incident of violence," Mr Davutoglu said in a late-night interview on NTV television.
His words were carried by the state-run Anadolu Agency Saturday.
Mr Davutoglu did not point to anyone as responsible for the incident but said the ruling AKP should not be blamed.
"If accusations are made even implicitly, I will react to them in a clear and open way," Mr Davutoglu said.
The HDP campaign has been the target of other attacks, including bomb explosions at two local party headquarters which injured six people last month.
The HDP has accused Mr Erdogan of making the party a target by constantly speaking against it in the campaign.
About 100 people were injured at the rally, mostly in the panic after the blasts.