Former Soviet leader Mikhail Gorbachev has died aged 91, Russia media report.

Mr Gorbachev, who took over in 1985, is best known for opening up the USSR and for his rapprochement with the West, but he was unable to prevent his country collapsing in 1991.

Many Russians blame him and his reformist policies for the country's demise.

The hospital where he died said he had been suffering from a long and serious illness.

Mr Gorbachev became general secretary of the Soviet Communist Party, and de facto leader of the country, at the age of 54.

He was at the time the youngest member of the ruling council known as the Politburo, and was seen as a breath of fresh air after several ageing leaders.

His policy of glasnost, or openness, allowed people to criticise the government in a way which had been previously unthinkable.

But it also unleashed nationalist sentiments in many regions of the country which eventually led to its collapse.

Internationally he reached arms control deals with the US and refused to intervene when eastern European nations rose up against their Communist rulers.

He is seen in the West as an architect of reform who created conditions for the end of the Cold War.