Inspectors of the Committee for the Prevention of Torture (CPT) reviewed Ocalan's health and prison conditions for the first time since 2007 during a visit in January at the invitation of the Turkish government.

The 62-year-old Ocalan has been serving a life sentence for treason since 1999 for the 25-year campaign his outlawed Kurdistan Workers' Party (PKK) -- considered a terrorist group by Ankara and much of the international community -- has been waging for Kurdish self-rule.

"Overall, the prisoner's health had improved since the 2007 visit. He still had recurrent nasal and other allergic symptoms but these were intermittent and did not seem to cause major health problems," the CPT said in a report released Friday.

"Further, his mental state has also improved since 2007 and can now be described as satisfactory, without any psychiatric disorder, although an underlying vulnerability persists," the report said.

Ocalan had been seen by nearly 90 different doctors in the past year and his exercise entitlement had been doubled, the report said.

Ocalan was the sole inmate at a prison on the island of Imrali until November last year when the Turkish justice ministry transferred five inmates and moved him to a new cell to allow contact between the prisoners.

"Compared to the regime previously applied to Abdullah Ocalan, the arrangements constituted a certain improvement," the report said.

"However, these new arrangements could only be described as a very modest step in the right direction," it said.

Complaints by Ocalan over his new prison conditions last year sparked major demonstrations in the majority Kurdish southeast of Turkey, resulting in three deaths.