DIYARBAKIR, Turkey (Reuters) - A bomb attack on a minibus killed 13 police officers in a Turkish province bordering Armenia and Iran on Tuesday, a government official told Reuters, the edge of a region beset by fighting between Kurdish militants and the Turkish state.

There was no immediate claim of responsibility for the bombing in the province of Igdir, but it comes after months of attacks by Kurdistan Workers Party (PKK) militants on soldiers and police officers in Turkey's largely Kurdish southeast.

More than 40 Turkish warplanes hit PKK targets overnight in northern Iraq, where the group has bases, in response to the killing on Sunday of 16 soldiers near the Iraqi border, the deadliest attack since a two-year ceasefire collapsed in July.

A security source said scores of PKK fighters were killed in the bombing raids. The PKK, which launched a separatist insurgency in 1984, is designated a terrorist organization by Turkey, the European Union and United States.

The renewed conflict, weeks before polls the ruling AK Party hopes will restore its majority, has shattered a peace process which President Tayyip Erdogan launched in 2012 in an attempt to end an insurgency that has killed more than 40,000 people over three decades.

It has also complicated Turkey's role in the U.S.-led fight against Islamic State group. A Kurdish militia allied with the PKK has been battling Islamic State group in northern Syria, backed by U.S. air strikes. But Turkey fears territorial gains by Syria's Kurds will fuel separatist sentiment among its own Kurdish population.

Dozens of F-16 and F-4 jets took part in the air operation in northern Iraq, which began around 10 p.m. (1900 GMT) on Monday and continued for six hours, the PKK bases in Qandil, Basyan Avashin and Zap, and hit weapons and food stores as well as the militants' machinegun positions.


The Igdir attack came as police traveled in a minibus to a border gate linking Turkey to the autonomous Nakhchivan enclave, sandwiched between Armenia and Iran and controlled by Azerbaijan, the Dogan news agency reported.

Erdogan said on Sunday that some 2,000 PKK militants had been killed since the conflict resumed in July. Around 100 members of Turkish security forces have been killed, based on information from government officials and security sources.

The PKK attacks have triggered nationalist anger against Kurds. The Istanbul branch of the pro-Kurdish Peoples' Democratic Party (HDP) said on Twitter that 126 of the party's buildings around the country were attacked on Monday.

Crowds near the Mediterranean city of Mersin closed a highway and attacked buses traveling to largely Kurdish regions, breaking windows with rocks, newspapers reported.

About 2,000 people overran a state construction project in Erzurum province, angry with a group of ethnic Kurdish builders suspected of sympathizing with the PKK, the leftwing daily BirGun said. CNN Turk news channel said Kurdish seasonal farm laborers in the town of Beypazari near the capital Ankara barely escaped a group that attempted to lynch them.

Separately, the PKK handed over 20 Turkish customs officials to human rights groups in northern Iraq on Tuesday, weeks after abducting them in the southeastern Turkish provinces of Hakkari and Van, the Turkish Human Rights Association said. Such abductions are not unusual and generally end with quick release of the officials.