Manama, Bahrain (CNN) -- A crush of protesters covered the streets of Bahrain's capital Tuesday in an anti-regime protest.
Tens of thousands of people marched in the biggest anti-government rally since the public disturbances in the island nation erupted last week, and chants of "No Shia, No Sunni, only Bahraini" and "The regime must go" rang through the multitudes tramping across the center of Manama.
The turnout was led by ambulance workers involved in rescuing some of those injured in the assault by security forces last Thursday on the Pearl Roundabout, which has been the epicenter of the Shiite-dominated protest movement.
The rally -- which comes after thousands of people attended a funeral for a protester slain last week -- was a massive display of popular scorn toward an embattled government working to forge stability. But it unfolded amid major gestures by the kingdom.
King Hamad touted a "national dialogue" and urged Bahrainis "to engage in this new process" and "move away from polarization," a government statement said Tuesday.
The king has held meetings with opposition members, community leaders and businesspeople "from all sections of society" to pave the way for a formalized dialogue process.
"The national dialogue is aimed at bringing to everyone in Bahrain the opportunity to contribute to Bahrain's future path of reform," the statement said.
The kingdom also ordered the release of a number of prisoners and closed cases against several Shiite leaders accused of plotting against the kingdom, the country's state news agency reported Tuesday.
That cleared the way for Hassan Mushaimaa, leader of Bahrain's largest opposition party, the Haq Movement, to return to the country from London. His aides said he was expected in Bahrain later Tuesday.
Mushaimaa's Haq Movement is more hard-line than the opposition Wefaq party, which includes 18 people in the 40-member parliament.
Many members of his movement are opposed to the government monarchy, but Mushaimaa said he will support the protesters whether they want a "new system in a constitutional kingdom" or want "to change the regime."
Mushaimaa, who had been living in exile, had previously been detained by the government for campaigning for more democratic rights in the island monarchy.
Bahrain last year asked the international police agency Interpol for help in arresting Mushaimaa, whom the government accused of a terrorist plot to destroy state buildings and of planning a coup.
But the king's decision closed the books on the case against Mushaimaa, giving him the freedom to return without fear of arrest.
An aide told CNN that Mushaimaa has been held up in Beirut, where he was stopped and held by airport security and questioned for hours.
The aide believes that this was because of the arrest warrant in September on charges of wanting to overthrow the government and he said that perhaps the wanted lists for Arab states haven't been updated.
The king also is working to "ensure that sectarianism does not take root in Bahrain."
Young members of the country's Shiite Muslim majority have staged violent protests in recent years to complain about discrimination, unemployment and corruption, issues they say the country's Sunni rulers have done little to address.
Protesters initially took to the streets of Manama last week to demand reform and the introduction of a constitutional monarchy. But some are now calling for the removal of the royal family, which has led the Persian Gulf state since the 18th century.
There were outbursts of government assaults on peaceful protesters last week, acts that drew international condemnation.
The Bahraini government statement said that seven people had died during protests in the nation and 25 people remained hospitalized. Protesters had given a higher death toll, placing the figure at 10 or 11.
Thousands of additional protesters moved into Pearl Roundabout on Monday, a growing gathering that has taken on an air of permanence since government forces retreated on Saturday and demonstrators reoccupied the symbolic location.
Tents, some of them outfitted with furniture and occupied by entire families, dot the epicenter of the Bahrain protest movement -- a setting similar to the one in Tahrir Square in Cairo, where Egyptians staged daily demonstrations that led to the removal of President Hosni Mubarak.
The Bahrain Center for Human Rights says authorities launched a clampdown on dissent in late 2010. It accused the government of torturing some human rights activists.