Amnesty International has demanded that the Kingdom of Bahrain release a leading human rights activist at risk of death after more than 50 days on hunger strike.

In a statement, Amnesty said Abdulhadi al-Khawaja, who has refused food since February 8, should be released immediately.

The rights group also reminded the Bahraini government to fulfill promises to release those jailed for protesting during last year's failed uprising.

Al-Khawaja was arrested in April for his role in protests by the country's Shiite majority against their Sunni rulers.

He was convicted by a specially convened court of anti-state crimes in June.

While the government has been able to quell large-scale protests on the streets of the capital Manama, demonstrators still gather in small groups in villages around the capital where they clash nightly with security forces.

Al-Khawaja was one of seven demonstrators sentenced to life imprisonment, with hundreds of other Bahraini protesters, including professionals such as doctors and nurses, also tried in the special court - set up after Bahrain imposed martial law last March to stamp out the unrest.

The Bahraini authorities have made pledges that they would release people who were imprisoned for exercising their right to freedom of expression, but the continued imprisonment of Abdulhadi Al-Khawaja demonstrates that they are not serious about fulfilling such promises, said Philip Luther,  Amnesty International's Middle East and North Africa Director in a statement.