Mikhail Gorbachev became the only president of the USSR in 1990

Mikhail Gorbachev, the last Soviet leader, told Russian media on Thursday that he is being treated in hospital for pneumonia.

Confirming a radio report about his illness, the 88-year-old told RIA Novosti news agency by phone: "It's true but I'm recovering. The treatment is basically over, now they are keeping me in for a couple of days and that's it."

Gorbachev led the Soviet Union from 1985 and spearheaded reforms aimed at greater public discussion and openness while his foreign policy achievements included defusing the US-Soviet nuclear standoff.

He became the only president of the USSR in 1990 but the reforms and freedoms he championed hastened the breakup of the multi-ethnic empire the following year and he is still widely reviled at home for this.

He has suffered ill health in recent years.