Eight prominent activists accused of plotting a coup in Bahrain during protests earlier this year have been sentenced to life in prison, according to the country's state news agency.

The court on Wednesday also sentenced other defendants, from among the 21 suspects on trial, to between two and 15 years in jail.

The Bahrain News Agency said the life sentences were issued against a prominent Shia political leader, Hassan Mushaima; activists Abdulhady al-Khawaja, Abduljalil al-Singace and five others.

Nabeel Rajab, president of the Bahrain Centre for Human Rights, told Al Jazeera that many people were unhappy about the sentences.

"Abdulhady al-Khawaja is one of the most respected human rights activist in the whole Arab region, so people are very angry," Rajab said.

"Hundreds of people have been brought up for charges in the past few days, and hundreds more are waiting to be tried."

Maryam al-Khawaja from the Bahrain Center for Human Rights said that Abdulhady al-Khawaja's daughter Zainab, was present in court when he was sentenced and stood up and chanted "Allahu Akbar" (God is Greater).

She was violently removed from court and arrested. She was later released after being charged with contempt of court and made to sign a pledge.

Alleged coup plot

Al-Singace, who was released in February after six months in jail, was also sentenced to life.

Nine of the defendants had been in custody on similar charges in the past before being set free under a royal pardon in February aimed at calming protests in the kingdom. Following the pardon, Mushaima returned to Bahrain from self-imposed exile in the UK.

Ibrahim Sharif, the Sunni leader of the secular leftist group Waad, was sentenced to five years. Waad had joined the largest Shia opposition group Wefaq in calling for political reforms.

Said Abdulnabi Shihab was also sentenced to life in absentia. Six other defendants who are abroad and being tried in absentia were sentenced to 15 years in prison.

Authorities claimed the activists had sought to overthrow Bahrain's Sunni monarchy and had links to "a terrorist organisation abroad".

Witnesses say demonstrators made roadblocks with sand and debris, and called for marches to oppose the trial. No violence was reported.

"We've seen today, since early in morning, that lots of protesters have blocked the highways and roads," Rajab said.

Demonstrations continue

On Tuesday night, several villages had demonstrated in solidarity with the opposition leaders facing charges.

Residents and activists said small protests broke out in some areas to chants of "Down, down (King) Hamad", as police cars rushed to block the roads to the villages.

The government contests the opposition's estimate that some 400 people are on trial, saying the number is far smaller.

Some activists sent telephone text messages calling on followers to protest again on Wednesday to demand the release of the defendants and rejection of the government's dialogue offer.

Four people have been sentenced to death and three others to life in prison over the killing of two policemen. Nine others were jailed for 20 years after being convicted of abducting a policeman.

Authorities have said 24 people were killed during the month-long unrest, most of them demonstrators.

Bahrain, home to the US Fifth Fleet, invited Saudi and other Gulf troops in mid-March to help crush  pro-democracy protests.