The last two weeks have seen a sharp surge in violence in the southeast, where the outlawed Kurdistan Workers' Party (PKK) has been waging an armed campaign for Kurdish self-rule since 1984.

On March 25, Turkish army troops killed 14 presumed PKK rebels, sparking several days of riots in the southeast and a wave of deaths on both sides.

In the lastest wave of attacks, security sources said on Saturday that six Kurdish militants suspected of involvement in the deaths of five soldiers were killed the previous day in clashes with an army commando unit in the southeastern province of Sirnak, near the border with Iraq.

A seventh militant was killed in a rural area near Batman, 180 kilometres (110 miles) northwest of Sirnak in a security sweep, Anatolia news agency reported. It said that 25 kilogrammes of explosives had been found at the scene of the fighting.

Two policemen, one a senior officer, were also killed and two others injured on Saturday when a mine exploded in the province of Elazig, about 400 kilometres (250 miles) northwest of Sirnak, CNN-Turk television channel quoted military sources as saying.

The surge in violence is thought to have been behind a short-lived hostage-taking in the northeastern city of Istanbul on Saturday.

Two men armed with air pistols took an employee and a customer hostage in a fast food outlet in the centre of the city before freeing their captives and given themselves up peacefully to police.

The men, aged around 25, were wearing identical T-shirts in the colours of the Turkish flag with "Turkey" blazoned across them, an AFP photographer at the scene reported.

They shouted "We are Turks" and "They are killing our soldiers" before handing themselves over to the large police force that had surrounded the building in the city's Taksim district.

They were thought to have been referring to troops killed in clashes with Kurdish militants.

The recent surge in violence began after the 14 Kurdish rebels were killed by the army.

In the protests and rioting that followed the rebels' funerals -- the worst urban unrest in the country for years -- 12 more people were killed. A further three died when PKK sympathisers threw petrol bombs in Istanbul.

In a separate development, Anatolia reported on Saturday that Turkish police had arrested a man they believe was behind a deadly bomb attack that killed five people in the seaside resort of Kusadasi last July.

Yilmaz Orhan, chief of police in the western Turkish province of Aydin, where the suspect was questioned, said the man had admitted to the offence.

"The suspect, according to his confession, placed four kilos of C-4 explosive under the seat of a minibus and exploded the bomb by calling from a public telephone to a mobile telephone connected to the explosive," Orhan said.

The suspect, identified only by the initials MSF, was arrested in Elazig on his return from a training camp organised by the PKK, Anatolia cited anonymous police sources as saying.

Five other people were arrested in Kusadasi on suspicion of being accessories to the bombing. Police had to disperse an angry crowd shouting anti-PKK slogans as the suspects were driven to court in the town.

Five people, among them a young British woman and an Irish teenager, were killed and 13 injured when the bomb exploded on a minibus in Kusadasi.

The conflict in the Kurdish majority southeast has claimed an estimated 37,000 lives and the PKK has been branded a "terrorist" organisation by Ankara, the European Union and the United States.