The protesters were demanding the release of Sheikh Ali Salman, the secretary general of the country's main opposition bloc, al-Wefaq National Islamic Society.

Bahraini regime forces fired teargas and birdshot to disperse anti-government protesters across several regions. Tensions have been running high in the monarchy since Salman’s arrest.

The arrests are part of Manama’s brutal suppression of anti-regime protesters since 2011. Scores of people have been killed and thousands more wounded during the crackdown.

Prosecutors on Monday charged Salman with attempting to overthrow the regime and sent him to trial despite international calls for his release.

He will stand trial from January 28 on charges of “promoting the overthrow and change of the political regime by force,” prosecutor general Nayef Mahmud said in a statement.

The opposition leader has been in custody since December 28 and his detention has sparked near-daily protests across the kingdom.

In a separate development, prominent Bahraini human rights activist Nabeel Rajab has been found guilty of insulting government ministries on Twitter and sentenced to six months in jail.

Meanwhile Human Rights Watch reviewed three of Salman’s recent speeches going back to October 2014 that are allegedly the basis of the charges against him, but could find nothing to support three of the charges or contradict his repeated and explicit disavowals of political violence.

Bahrain should immediately release the head of the country’s leading political opposition group having failed to present any evidence that justifies his detention. Sheikh Ali Salman, the secretary general of Al Wifaq, a legally recognized political society, has been in detention since his arrest on December 29, 2014, and has been charged with various criminal offenses, which include the promotion of violence and defamation of a “statutory body”, Human Rights Watch announced.

Since the Bahraini authorities have produced no such evidence despite the fact that all the speeches that Sheikh Salman has given in the last three years are recorded and are in the public domain, they should release Salman immediately, and if none can be produced, drop the charges against him, Human Rights Watch said.

“Bahrain’s allies in London, Paris, and elsewhere have largely stayed silent as Bahrain has filled its jails with the people who hold the key to the political solution the UK and US claim to support,” Stork said. “Who will Bahrain have to detain and on what nonsensical charges before Bahrain’s allies speak out?”