Kurdish rebel leader Abdullah Ocalan presented his closing statement at his treason trial today, warning the court that Turkey would be plunged into bloodshed if it ignores his calls for peace and sentences him to death.

Standing in a bulletproof glass cubicle, his hands clasped below his abdomen, Ocalan, 51, threatened and cajoled prosecutors during a spirited and articulate defense at his trial on this prison island in the Sea of Marmara, south of Istanbul.

"The chapter of rebellions, of [Kurdish demands] for a separate state needs to be closed," he said during the nearly three-hour statement. "I will use all my strength to end the bloodshed . . . to work for peace in a democratic Turkish republic. "If we don't seize this chance, things could get a lot worse."

Prosecutors are seeking a sentence of death by hanging for Ocalan, who is accused of masterminding a bloody 15-year-long campaign for Kurdish independence in Turkey's largely Kurdish southeastern provinces. The insurgency launched by his outlawed Kurdish Workers' Party (PKK) is blamed for more than 30,000 deaths.

A verdict in the trial, which began May 31, is expected early next week and is almost certain to be a conviction. Despite his repeated calls for peace during the trial, Ocalan has admitted to leading the PKK, which the Turkish government regards as a terrorist organization.

There is strong public sentiment for a death sentence, which would have to be endorsed by parliament. But Turkey has not carried out an execution since 1984, and officials say there is a growing debate within the government and the country's powerful armed forces about whether Ocalan should be hanged if he is convicted.

The Strasbourg-based Council of Europe is threatening to suspend Turkey's membership if Ocalan is executed. An execution also could undermine Turkey's efforts to host President Clinton and other leaders at a summit of the 55-nation Organization for Security and Cooperation in Europe, which is scheduled to take place in Istanbul in November. Its theme is human rights.

But officials here say their main worry is that Ocalan may be replaced as de facto leader of the country's estimated 12 million Kurds -- 20 percent of the population -- by an even more effective and charismatic figure.

Sources close to the rebels confirm that while they publicly endorse Ocalan's calls for peace, many feel betrayed by his apparent rejection of the goals for which 20,000 Kurdish rebels have died.

"Kurdish independence, federation or autonomy, these are not needed," Ocalan told the court today. "Our problems must be solved . . . within the framework of the unitary Turkish state."

As if to underscore his differences with the rebels, Ocalan accused rogue factions within the PKK of disregarding his demands to stop attacking civilians. "The PKK," he said, staring at the panel of judges, "has become very dangerous. . . . We must work together to disarm them . . . to stop the terror."

Still, Ocalan also blamed the Turkish government's repressive policies against the Kurds for a string of Kurdish uprisings. In particular, he blamed a ban on the Kurdish language that was not lifted until 1991 for fueling his own insurgency.

Ocalan said granting Kurds the right to broadcast and publish in their own language would go a long way toward meeting their demands for cultural rights. "If not," he warned, "there will be 10 more PKKs and many more Ocalans."