Main Bahraini opposition groups have boycotted the countrys national reconciliation talks to protest against the arrest of a top opposition figure.
The coalition of five groups, including the main opposition party al-Wefaq, said on Wednesday that it has suspended its participation in the talks until further notice.
The decision was made a day after Khalil al-Marzooq, a former deputy speaker of parliament, was arrested over his recent anti-regime remarks.
Head of Bahrains public prosecution, Nayef Yousif, has accused Marzooq of instigating violence and having links to a group authorities blame for bombings and other attacks. He also said Marzooq is under investigation and will be held for 30 days.
Marzooq served as deputy speaker in the countrys 40-member parliament before a walkout was staged in 2011 by 18 members of al-Wefaq in protest against the violent crackdown on anti-regime demonstrators.
Numerous rounds of talks have failed to significantly heal the rifts between the opposition and the Manama regime since the beginning of anti-regime protests in Bahrain.
The first round of talks, which were held in July 2011, collapsed after the opposition walked away from the talks, saying they were not carried out fairly.
Bahrainis have been staging demonstrations since mid-February 2011, demanding political reforms and a constitutional monarchy, a demand that later changed to an outright call for the ouster of the ruling Al Khalifa family following its brutal crackdown on popular protests.
Scores have been killed, many of them under torture while in custody, and thousands more detained since the popular uprising in Bahrain began.
Protesters say they will continue holding anti-regime demonstrations until their demand for the establishment of a democratically-elected government and an end to rights violations are met.