°®Âþµº

Bahrain's interior ministry on Monday announced sentencing changes for hundreds of inmates in the Gulf monarchy, which activists have said should result in the release of scores of political prisoners.

Authorities gave the green light for "replacement of custodial sentences with an alternative sentence," for 340 inmates, the ministry said, with 99 further prisoners allowed more lenient arrangements in custody under Bahrain's "open prison programme".

The Bahrain Institute for Rights and Democracy (BIRD) said under the changes "340 inmates of Jau Prison will have their prison sentences replaced... meaning that they will be released," referring to a prison in the south of the island nation.

The UK-based group said while the figures were uncertain, it "anticipates that at least 100 political prisoners will be included, leaving approximately 300 political prisoners still incarcerated in the country".

Bahrain denies holding political prisoners, although dissidents have been detained since Shia-led Arab Spring protests in 2011 were put down by the authorities, backed by Saudi forces.

Scores of inmates were released this month following a royal pardon concerning 457 inmates, according BIRD.

The move came five months after a pardon of more than 1,500 inmates - the biggest in years.

"This is another step in the right direction to end the era of political imprisonment in Bahrain," Sayed Alwadaei, BIRD's head of advocacy, said.

"We call for the immediate release of all arbitrarily detained political prisoners, including high-profile human rights defenders and opposition activists and those facing death row," he added.

BIRD and 28 other organisations, including Human Rights Watch, sent a letter on Monday to members nations of the UN General Assembly, meeting this week in New York, urging them to raise the issue of human rights in Bahrain.

In August, three UN rapporteurs called on Bahrain to take immediate steps to guarantee the rights of detainees in Jau prison, pointing to allegations of ill-treatment.