|Twenty one opposition activists were sentenced for involvement with a months-long protest movement [EPA]
A special Bahrain security court has rejected appeals by 21 opposition activists who were convicted in June of plotting to overthrow the government.
Wednesday's decision suggests Bahrain's authorities are not willing to roll back punishments for those considered central to the anti-government uprising.
Some officials have taken steps to ease tensions, including the release of some detainees and reinstatement of state workers purged for suspected support of the seven-month-old protest movement.
Bahrain's security forces, backed by a Gulf military force led by Saudi Arabia, have crushed large-scale demonstrations by the country's majority Shias Muslims.
But protesters have maintained their shows of dissent, turning into daily clashes between police and demonstrators, across the strategic island which is home to the US Navy's 5th Fleet.
Speaking to Al Jazeera, Nabeel Rajab, of the Bahrain Centre for Human Rights, called the trial unfair, saying that the charges should have been dismissed.
"As you know - as everyone knows - they are being tried in a court that does not meet any international standards for a fair trial," he said of the activists.
"It is a military court ... a lot of human rights organisations, a lot of countries, a lot of governments, have urged Bahrain to stop those courts ... but unfortunately, Bahrain is continuing, going ahead with more and more people brought before the military court."
|Read our complete coverage of the protests in Bahrain
Rajab said it is expected that more doctors and nurses will be brought before the military courts.
The initial verdicts in June against the 14-member group touched off intense street battles and brought swift condemnation from international rights groups.
The appeal group included eight well-known political figures sentenced to life in prison after being charged as coup plotters.
They include the prominent Shia political leaders, Hassan Mushaima and Abdul Jalil al-Singace, and Abdulhadi al-Khawaja, a rights activist.
Mushaima returned from self-exile in London earlier this year after Bahrain's leaders promised to erase old charges of opposing the state.
Among those sentenced to life imprisonment, all but one of the defendants are in Bahrain. Among the rest, some were sentenced in absentia, and received shorter prison terms, apparently because they were not considered leaders.
Defence lawyers say they plan to appeal the security court's decision to the country's highest civilian court.
In the rubbish-strewn streets of Sanabis, 2km west of Manama, the police are on the prowl for the culprits.
A group of Shia teenagers and women, some of them mothers, some of them single, scuttle into a nearby house, putting out the lights as men get out of cars and drag some boys down from a rooftop across the street.
The incriminating item is hurriedly stuffed down the back of a sofa, letting out a small noise which threatens for a few seconds to give the game away. But the danger passes. The police move on and the small plastic bugle is whipped out once more.
The vuvuzela - used here to pipe out the phrase "Down with Hamad," Bahrain's king - has become one of the mundane props in a game of brinkmanship between the Sunni Muslim ruling elite and majority Shia who see confirmation in the daily clashes with police that they are oppressed.
"All people are doing is shouting slogans or using a bugle. But police are entering people's houses and arresting them," says one of the women, an unmarried government employee.
Bahrain, where Shias represent about 70 per cent of the population, has been in turmoil since pro-democracy protests, inspired by revolts in Egypt and Tunisia, took to the streets in February.
More than 30 people have died since the unrest began in February, inspired by other Arab revolts. Hundreds of others have been arrested or driven out of jobs or studies.