The top European human rights body has called on Turkey to allow independent observers into a mainly Kurdish town where a 24-hour curfew has been imposed as security forces battle suspected Kurdish militants.

Nils Muiznieks, human rights commissioner for the Council of Europe, expressed concern about allegations of "disproportionate use of force" against civilians in Cizre, a town near the Syrian border which has been under curfew since September 4.

Interior minister Selami Altinok said seven suspected Kurdish rebels and one civilian had died in clashes in the town, but a pro-Kurdish opposition party said 21 civilians had been killed.

"I have received serious allegations of disproportionate use of force by security forces against civilians," Mr Muiznieks said.

"I urge the authorities to ensure immediate access to Cizre by independent observers in order to dispel the rumours of human rights violations perpetrated by security forces. I hope for a quick end to this emergency situation."

The town is under a virtual news blackout and activists say the curfew has severely disrupted life in the town of 100,000 inhabitants, with people complaining of shortages of food and medical services.

Authorities this week barred a delegation of pro-Kurdish party officials from entering Cizre.

Deputy prime minister Cevdet Yilmaz said the delegation was prevented from entering for its own safety.

Turkey has seen spiralling violence since July, with hundreds reported killed in the renewed conflict between security forces and the Kurdistan Workers' Party, or PKK - including more than a hundred soldiers and police officers.

The renewed fighting has shattered a peace process with the Kurds that was launched in 2012.

The Turkish government has vowed to fight the rebels until the group agrees to disarm. The PKK is considered a terrorist organization by Turkey and its western allies.

Elsewhere, a waiter was killed and three policemen were injured when suspected Kurdish rebels opened fire on the officers at a restaurant in the majority-Kurdish city of Diyarbakir.

Turkey has been carrying out airstrikes against PKK bases in northern Iraq and earlier this week sent ground troops for a "short-term" cross-border operation in pursuit of a group of rebels who reportedly escaped after an attack that killed 16 troops.

The state-run Anadolu Agency said 21 jets were involved in a fresh round of strikes overnight, targeting seven PKK camps in northern Iraq, with security sources saying as many as 60 rebels were killed.