One Turkish soldier and three suspected members of the outlawed Kurdistan Workers' Party (PKK) were killed in eastern Turkey in new violence blamed on the Kurdish rebels, the state media said Sunday.

Fighting erupted in the early hours of Sunday near Kagizman town in eastern Kars province during a security sweep of the area, the official Anatolia news agency reported.

Two soldiers were wounded and one of them later succumbed to his injuries in hospital, Anatolia said, adding that the security forces had shot dead three PKK militants.

Ankara is currently waging a two-pronged "anti-terror" offensive against Islamic State (IS) jihadists in Syria and PKK militants in northern Iraq and the southeast of Turkey following a wave of attacks.

But, so far, air strikes have overwhelmingly concentrated on the separatist Kurdish rebels, who have responded by tearing up a 2013 ceasefire and waging a bloody campaign against the security forces.

More than 40 members of the Turkish security forces have been killed in violence linked to the PKK since the crisis began on July 20 when a suicide bombing blamed on IS left scores of pro-Kurdish activists dead in the town of Suruc.

Since Friday alone, at least eight members of the Turkish security forces have been killed in attacks blamed on PKK militants in the country's Kurdish-majority east and southeast regions.

Meanwhile an open-ended curfew has been declared in the Varto district of eastern Mus province following heavy clashes between the Turkish army and PKK militants, Anatolia said.

The clashes erupted overnight after the PKK youth wing demolished a bridge with bulldozers they had seized, according to Anatolia.

The PKK, designated as a terrorist organisation by Turkey, the EU and the United States, took up arms for self-rule in the southeast in 1984, and the conflict has since claimed tens of thousands of lives.