By Umit Bektas
ANKARA (Reuters) - Two militants believed to be preparing a car bomb attack detonated explosives and were killed near Ankara on Saturday after Turkish police told them to surrender, the provincial governor said.
The blast, which he saw as linked to the Kurdistan Workers Party (PKK) armed group, coincided with a fresh spate of violence in the mainly Kurdish southeast which killed 12 people, with police gunfire killing four of them, authorities said.
"It looks like there is a high probability of a PKK link," Ankara Governor Ercan Topaca told reporters at the scene of the explosion outside the capital, describing the militants as one male and one female.
Video footage showed forensic teams in white overalls inspecting the site as police secured the area around a hut in flat countryside on the road to the town of Haymana.
"A big disaster was prevented. They were probably going to attack Ankara," Justice Minister Bekir Bozdag told broadcaster CNN Turk in an interview, also pointing the finger at the PKK.
"...Turkey is in a critical position. There are clashes in Syria and Iraq and sources of terror there."
The PKK leadership is based in the mountains of northern Iraq and Syria's Kurdish YPG militia has close ties to the group. A rebel operation backed by Turkey in Syria aims to push both jihadist group Islamic State and YPG forces away from the border.
On Turkey's border with Iraq, in the Cukurca district, Turkish troops killed eight PKK militants in the latest clash on Friday, the military said in a statement.
Further east near the Iranian border, four people were killed and two seriously wounded by gunfire from an armored police vehicle in the town of Yuksekova, the local governor's office said in a statement.
It said the officer in the vehicle's gun turret was detained by colleagues and an investigation launched, citing the officer as saying the gun had gone off without him touching the trigger.
"The massacre today heightens fears that there has been a move to a regime of public executions. This provocation directly targets the people," the pro-Kurdish Peoples' Democratic Party (HDP) said in a statement.
President Tayyip Erdogan was to chair a security meeting with military and political leaders in Istanbul on Saturday, sources from his offices said. The reason was not clear.
At the scene of Saturday's explosion in Ankara, police seized two pieces of plastic explosives and 200 kg (440 pounds) of ammonium nitrate, the governor's office said in a statement. Ammonium nitrate is an ingredient in bomb-making.
It said security forces moved against the militants at 6:00 am (2300 EST) at a stud farm 30 km (19 miles) from the capital after a tip-off from the main southeastern city of Diyarbakir.
An identity card found at the scene, believed to belong to one of the would-be bombers, was of a man from the southeastern province of Bingol. A third individual was also being sought, the governor said.
The PKK has fought a three-decade-old insurgency which has killed more than 40,000 people. It is designated a terrorist group by Turkey, the United States and the European Union.
A two-year-old ceasefire between the group and the Turkish state collapsed in July last year, triggering renewed violence.
On Thursday a bomb attack near a police station in Istanbul wounded 10 people. The Kurdistan Freedom Hawks (TAK), a PKK offshoot, claimed responsibility for that blast.
(Writing by Daren Butler; editing by Mark Heinrich and Stephen Powell)