Witnesses in Bahrain say riot police have fired tear gas at protesters who were denouncing reconciliation talks between the Gulf kingdom's Sunni rulers and the Shia opposition.
The renewed violences came late on Saturday, hours after opposition and pro-government groups began talks aimed at healing the deep rifts caused after protests earlier this year were brutally repressed.
The protesters gathered near a landmark square in the capital Manama, that had been the epicentre of the pro-democracy uprising that began in February.
The witnesses spoke on condition of anonymity for fear of harassment by authorities.
Scepticism over national dialogue
The opposition has expressed scepticism over whether the national dialogue, decreed by King Hamad bin Isa al-Khalifa, can accomplish anything, noting that it only has 35 of the 300 seats at the bargaining table.
"We start without conditions or limits, our only condition is accepting one another," Khalifa bin Ahmed al-Dhahrani, chairman of the dialogue and also a speaker of parliament, said on Saturday.
Isa Abdulrahman, a government spokesperson, said the environment in Bahrain is conducive to fruitful negotiations between the Sunni ruling elite and the opposition.
He described the "the high turnout" to the talks as a testament to the absence of concerns for participants.
"When you reach a percentage of 94 per cent of the people that you have invited to attend the dialogue, they have accepted, willingly, to take part in the dialogue,” he said.
Abdulrahman said around 80 per cent of participants have submitted proposals that will be discussed over the coming month.
The Gulf Arab kingdom off the coast of Saudi Arabia is strategically important, hosting the headquarters of the US Navy's Fifth Fleet.
Washington was encouraged by "the decision of Al-Wefaq, Bahrain's largest opposition political society, to join the national dialogue recently announced by King Hamad," Mark Toner, a spokesperson for the US state department, said.
Inspired by uprisings in Tunisia and Egypt that toppled rulers in the two countries, Bahrain's Shia, who say they are discriminated against, took to the streets in February and March to demand political reforms.
The nation's Sunni rulers crushed the movement with martial law and help from security forces from Saudi Arabia and the United Arab Emirates.
An estimated 30 people died, hundreds were arrested and thousands of Shias lost their jobs.
Hardline Sunnis accused the mostly Shia protesters of a sectarian agenda backed by Iran and its Shia government across Gulf waters.
Bahrain has historically been the nexus point for tensions between Gulf Sunni monarchies and Iran.
Hoping to defuse tensions, the king lifted martial law a month ago and called for a dialogue to discuss political, economic, social and legal reforms with "all options" on the table.
After lengthy internal debate, Wefaq, the leading Shia opposition group, decided to join the dialogue but threatened to pull out if talks did not move toward greater representation in government.
Bahrain has an elected assembly but the ruling al-Khalifa family appoints cabinet ministers and the upper house.
Khalil al-Marzooq, a senior Al-Wefaq official, said the group's five-strong delegation would maintain its demand for the prime minister to be drawn in the future from the majority bloc in parliament, Al-Wasat newspaper reported.
"The whole of Bahrain will be much better if we have an elected government," al-Marzouq said.
Wefaq has complained that it is under-represented and that there are too many people to reach any meaningful consensus.
Dhahrani told participants that any agreed proposals would be taken to the king, who "will pass it on to legal organisations for the necessary implementation".
The forum has received hundreds of proposals for discussion.
'Freedom for all prisoners'
Discussions on Saturday were mostly ceremonial, with a recital from the Koran, a speech and presentations.
By early afternoon, the main hall was empty and only one sub-group appeared to be in talks in a separate room.
Leading up to the start of the dialogue, the government offered some concessions, including the launch of an investigative panel led by Cherif Bassiouni, an Egyptian-American war crimes expert who is also heading UN inquiry into events in Libya.
Most, though not all, Saudi troops are being withdrawn and there are fewer armoured vehicles and tanks on the dusty streets of Manama, although checkpoints still dot the streets.
King Hamad, in a speech televised on the eve of the talks, said: "It will be a true dialogue in every respect and no section of Bahrain's wide and diverse society will be ignored."
Hours before the King's speech, more than 20,000 Shia crowded the centre of the town of Diraz at a Wefaq rally, demanding to be heard and waving Bahraini flags.
"No dialogue with al-Khalifa" and "Freedom for all prisoners", they shouted.
A week earlier, eight prominent Shia opposition leaders were sentenced to life in prison, and small nightly protests erupt in Shia villages, only to be snuffed out by police with tear gas.