Clashes in Turkey overnight killed one soldier and three Kurdish militants, the latest in the heaviest fighting the country has seen in more than a decade, security sources said on Sunday.
Fighting erupted outside the south-eastern town of Tunceli after two groups of Kurdistan Workers Party (PKK) fighters simultaneously attacked two military outposts, the sources said.
More than 700 people have been killed since national elections in June last year, making this the deadliest period since the capture of PKK leader Abdullah Ocalan in 1999, the International Crisis Group said in a report this month. The upsurge in violence has been linked by some to the failure of secret peace talks, thought to be held in 2010, between the PKK and Turkish intelligence officers in Oslo.
Prime Minister Tayyip Erdogan accuses neighbouring Syria of arming the rebels, who are mainly based in northern Iraq. Erdogan has been an outspoken critic of President Bashar al-Assad's 18-month-old crackdown on a popular uprising.
The PKK took up arms against the Turkish state in 1984 to establish an ethnic homeland. More than 40,000 people, mainly Kurds, have died in the violence. The PKK has since scaled back its demands to greater political autonomy and cultural rights for Turkey's 15 million ethnic Kurds.