Ankara, Feb. 7 (AP): Imprisoned Kurdish rebel chief Abdullah Ocalan, suffered a mild heart spasm, but he was in stable condition, a Turkish official said on Tuesday.

Ocalan had been suffering from heart problems, said the official, who was speaking on condition of anonymity because he is not authorized to speak to the media. The official said Ocalan's heart problems largely stemmed from him being overweight.

A Turkish intelligence Web site, Acik Istihbarat, also reported that Ocalan had a heart problem.

Ocalan has been in solitary confinement on the prison island of Imrali, near Istanbul, since his capture in 1999. Kurdish guerrillas have been fighting for autonomy in the southeast since 1984. The fighting has claimed about 37,000 lives.

His guerrilla group and sympathizers have long expressed concern about Ocalan's health and demanded that he must be moved out of solitary confinement.

Kurds often stage violent demonstrations to call an end to the rebel chief's isolation. The report about Ocalan's heart problem might trigger further protests.

Turkey maintains that doctors closely monitor Ocalan's health.