Separatist Kurdish rebels from Turkey announced Tuesday they had called off a cease-fire that had been in effect the past four years. They say the cease-fire was ending because the Turkish government had failed to respond in kind.

In a statement carried by the pro-Kurdish MHA news agency, the rebel group, previously known as the PKK and now called KADEK, said the cease-fire declared in 1999 was no longer sustainable.

But the rebels said they did not plan an immediate resumption of their armed campaign against the Turkish state. That campaign ended in 1999 following the capture of their leader, Abdullah Ocalan. Ocalan, who is serving a lifetime sentence on treason charges, renounced his demands for Kurdish independence at that time, saying that Turkey's 14 million Kurds would settle for cultural autonomy instead.

He ordered his men to withdraw to Kurdish controlled northern Iraq where some 5,000 KADEK guerrillas are currently based.

Despite occasional clashes in Turkey's largely Kurdish southeast region, the cease-fire has been largely holding.

The rebels blame the Turkish government's refusal to negotiate a peace agreement with them for their decision to end the ceasefire.

The government labels the guerrillas terrorists and has ruled out any talks with them.

In line with efforts to become a full member of the European Union, Turkey has enacted a series of democratic reforms in recent months that include easing bans on broadcasting and education in the Kurdish language.

In a further attempt to win back the country's alienated Kurdish population, the Turkish parliament in August approved an amnesty law for rebels who can prove they were not involved in any violence. It additionally allows reduced sentences for those rebels who provide information on their fellow fighters.

The group rejected the law because it does not cover the KADEK leadership. About 10 rebels have turned themselves in since the law was passed.