The attack saw Kurdistan Worker's Party (PKK) rebels target a military vehicle carrying troops to guard duty in the southern city of Iskenderun, Deputy Prime Minister Bulent Arinc said.

He raised the death toll from six to seven, adding that seven other soldiers were also wounded in the attack.

"We condemn the separatist terrorist organization that is behind this inhumane attack," Arinc said, using the official jargon for the PKK which has been leading a 25-year insurgency against the Turkish government.

Additional troops were deployed in the Iskenderun area and a security operation was underway to catch the assailants, he added.

Three of the wounded soldiers were in a critical condition and were taken to a military hospital in Ankara.

There was no immediate claim of responsibility by the PKK, an outlawed separatist group whose leader Abdullah Ocalan has decided to abandon efforts to seek dialogue with the Turkish government.

Five members of Turkey's security forces were killed Saturday in a string of attacks that gave a strong sign that efforts for peace between the Turkish government and the rebels are unravelling.

Army chief General Ilker Basbug cut short a visit to Egypt after the rocket attack and a deadly Israeli operation on an aid convoy headed to the Gaza Strip, which included several Turkish vessels.

Ocalan was jailed for life in 1999 but has retained his influence over the PKK from his prison cell on Imrali island, often issuing guidelines to rebels in statements released through his lawyers.

His calls for dialogue have been rejected by the government, which insists the PKK either lays down its arms or faces the army, and he was quoted in a party mouthpiece over the weekend as having given up his pursuit of dialogue.

"Keeping up this process is no longer meaningful and useful. I am quitting after May 31 since I could not find an interlocutor," Ocalan was quoted by Saturday's Ozgur Politika newspaper as telling his lawyers during a recent prison visit.

Ocalan however said his decision did not amount to a call for the PKK to intensify its armed campaign.

"This should not be misunderstood. This is not a call for a war," he said, according to Ozgur Politika.

Following a usual winter lull, violence has broken out anew in the southeast. The melting of winter snow has allowed the rebels to move out from their mountain hideouts in Turkey and neighbouring Iraq.

The PKK, listed as a terrorist group by Turkey and much of the international community, took up arms in 1984 for self-rule in Turkey's Kurdish-majority southeast, sparking a conflict that has claimed some 45,000 lives.

Last year, Prime Minister Recep Tayyip Erdogan's government announced it would expand Kurdish freedoms in a bid to peacefully end the conflict.

The initiative however has faltered, amid bitterness over the government's decision to ban the main Kurdish party and public outrage at bloody PKK attacks.