Gunmen burst into the office of Deryan Aktert, an AK Party official in the southeast, as PKK claims responsibility.

A local official from Turkey’s ruling party has been shot and killed in the country’s southeastern region, where Kurdish fighters affiliated with the outlawed Kurdistan Workers Party (PKK) operate.

The PKK said on Tuesday it was behind the killing, the second such shooting in as many days in the country’s restive southeast.

Deryan Aktert, who headed the AK Party’s branch in Diyarbakir’s Dicle district, was attacked in his office on Monday at 10:30pm local time (19:30 GMT), the provincial governor’s office said.

PKK’s armed wing said on its website fighters targeted Aktert for his cooperation with the state in its fight against the group, which is listed as a “terrorist” organisation by Turkey, the United States and the European Union.

PKK, which launched its armed separatist rebellion in 1984, rejects the designation.

The group – in a growing conflict with security forces in the region bordering Iran, Iraq and Syria – has been behind a spate of recent attacks.

Ebubekir Bal, an AK Party parliamentarian representing Diyarbakir, said armed men had previously attacked Aktert’s office last year, according to Reuters news agency.

A day earlier, assailants killed Aydin Mustu, the ruling party’s deputy leader in the Ozalp district of Van, a city 350km to the east of Diyarbakir.

Also in recent days, officials have blamed the PKK for bombings – both successful and failed attempts – throughout the country, including one just outside the country’s capital on Saturday and another that killed 18 people on Sunday in Hakkari province.

Police in Diyarbakir said they had also detained 55 officials from the pro-Kurdish Peoples’ Democratic Party and its sister Democratic Regions Party on Tuesday in a “counterterrorism” investigation.

A two-year ceasefire with the PKK collapsed in July last year, adding to the turmoil in a region already struggling with the civil war in Syria and the rise of the Islamic State of Iraq and the Levant group (ISIL, also known as ISIS) there and in Iraq.

Since then, more than 600 Turkish security personnel and thousands of PKK fighters have been killed, according to the state-run Anadolu news agency.