Tynchbek Akmatbayev was said to be in prison to inspect conditions

Tynchbek Akmatbayev was shot dead after being taken hostage during a visit to Moldavanovka prison, about 25km (15 miles) outside the capital, Bishkek.

The others who died are said to have been members of his entourage. The head of the prisons service, Imatulla Polotov, was critically injured.

The killings come after two days of unrest at nearby Novopokrovka prison.

Inmates there have been protesting about bad food, damp accommodation, inadequate clothing and a lack of hot water.

Mr Akmatbayev, a prominent MP, was chairman of a parliamentary committee on security and policing.

He had been involved in negotiations with prisoners at Novopokrovka, about 20km (12 miles) east of Bishkek, where inmates were said to have forced prison officers outside the building.

Beaten

He and his entourage were in the tuberculosis hospital attached to Moldavanovka prison on a visit to assess living conditions when they were taken hostage.

"Akmatbayev was shot dead," said Sergei Sidorov, spokesman for the sentencing board.

Mr Polotov was severely beaten but survived.

Prime Minister Felix Kulov is reported to have gone to the prison and successfully negotiated the release of Mr Akmatbayev's body.

A prison official told a news agency that the guards had vacated the prison, leaving it in full control of the approximately 450 inmates.

He could not say how the prisoners acquired weapons.

An official said the situation at the other prison in Novopokrovka was now calm.

Kyrgyzstan has witnessed several violent incidents since the overthrow of ex-President Askar Akayev in March.