(CNN) -- Three hard-line groups in the Gulf kingdom of Bahrain have united and called for the ruling family to step aside, they announced.
The Haq, Wafa and Bahrain Freedom Movement parties have formed a "Coalition for a (Bahraini) Republic," the groups said late Tuesday.
"The people want to overthrow the regime," said Hassan Mushaima, secretary general of Haq movement, at a news conference. Video of the event was posted on YouTube.
He said the coalition was "motivated by the rules of our Islamic religion and international charters on human rights to freely decide their faith, and expressing our gratitude to the Bahraini community who suffered from the rule of the corrupt family of Al-Khalifah."
Anti-government protesters have been camped out in the Pearl Roundabout in the capital city, Manama, for nearly a month.
The new coalition is calling for a democratic republic with no ruling family -- a step further than other opposition groups, which are calling for a constitutional monarchy.
It appeared the hard-line groups represented a minority of the protesters at the roundabout, with more moderate protesters in the majority.
The government has promised to build 50,000 new housing units and hire an additional 20,000 police officers, roughly doubling the size of the force, amid protests.
Members of Bahrain's majority Shiite Muslim community are not allowed to join the force. Sunni Muslims -- a majority worldwide, but a minority in the kingdom -- dominate the government of Bahrain.
A large number of people protested outside the palace where Bahrain's cabinet was meeting Sunday, the first time a protest had been allowed at the site.
Protesters chanted slogans calling for the downfall of Prime Minister Sheikh Khalifa Bin Salman Al-Khalifa.
The protest, which lasted about 2 1/2 hours, was peaceful and broke up before the Cabinet meeting ended.
Anti-government demonstrators remain at the Pearl Roundabout, where seven people died when security tried to clear the area in mid-February.
More than 500 people have been injured in Bahrain since the protest began as part of a wave of popular unrest crashing through the Arab world, according to human rights activists.
A few dozen of those injured remain in the hospital. Four of them are in serious condition, said Nabeel Rajab, president of the Bahrain Center for Human Rights.
Protesters initially took to the streets of Manama to demand reform and the introduction of a constitutional monarchy.
The royal family has led the Persian Gulf state since the 18th century.
Sunday, Crown Prince Salman bin Hamad Al Khalifa addressed the nation on television, saying that a consensus has emerged around 70% to 80% of the people's demands, according to a release from the government.
"Everybody wants better services. Everybody wants dignity. Everybody wants to be heard," he said.
"Instead of having winners and losers, let's have victory for all, security and stability for all, and respect for all."
Bahrain's king reshuffled his cabinet last month as protesters continued to call for reforms. He has also touted a "national dialogue" and urged Bahrainis "to engage in this new process" and "move away from polarization."
"Today we are drawing the future of a country," the crown prince said. "I can assure you that Bahrain will not go back to its former state because the one thing that is certain in life is change."
The young Shiite Muslim majority has staged protests in recent years to complain about discrimination, unemployment and corruption, issues they say the country's Sunni rulers have done little to address.
The Bahrain Center for Human Rights said authorities launched a clampdown on dissent in 2010. It accused the government of torturing some human rights activists.
CNN's Jenifer Fenton contributed to this report.