More than 1,000 Saudi troops have entered Bahrain where anti-regime protests have raged for over a month, a Saudi official said Monday, as demonstrators took over Manama's central business district.
Pro-democracy protesters poured into the banking hub, witnesses said, as Saudi forces appeared poised to help the embattled government restore order in the strategic Gulf kingdom, home to the US Fifth Fleet.
The Saudi troops entered Shiite-majority Bahrain on Sunday as part of the Gulf countries' joint Peninsula Shield Force, the Saudi official told AFP, requesting anonymity.
The intervention came "after repeated calls by the (Bahraini) government for dialogue, which went unanswered" by the opposition, he said.
The Bahraini government has not confirmed the presence of Saudi troops in the archipelago, which has been ruled by a Sunni dynasty for more than 200 years.
But the website of Bahrain's Al Ayam newspaper, which is close to the Al-Khalifa royal family, said forces from the six-state Gulf Cooperation Council were expected to enter Bahrain to help boost security.
Helicopters buzzed over the Financial Harbour business complex, which was blocked off by protesters, a day after more than 200 people were injured there in clashes between riot police and demonstrators, residents said.
Sunday was the worst day of violence in the tiny Gulf kingdom; seven people were killed at the start of anti-regime unrest a month ago.
Bahrain -- which is joined to Saudi Arabia by a causeway across the Gulf -- has become a regional financial hub as it seeks to diversify its economy away from dependence on diminishing oil revenues.
But to many of the country's disenfranchised Shiites the banking district is a symbol of corruption, wealth and privilege.
Police appeared to have deserted the area, while shopping malls and office towers were closed, witnesses said.
Protesters continued to hold a sit-in at Pearl Square just outside the financial district, while others were blocking roads leading to the business district.
The Shiite-led opposition alliance said any foreign force would be treated as an invading army.
"We consider the arrival of any soldier, or military vehicle, into Bahraini territory... an overt occupation of the kingdom of Bahrain and a conspiracy against the unarmed people of Bahrain," said an opposition statement.
Most workers seemed to be following a trade union call for a general strike to protest violence by the security forces.
The Saudi intervention comes two days after US Defense Secretary Robert Gates visited Manama and urged King Hamad to undertake rapid and significant democratic reform, not just "baby steps."
Gates told reporters after the talks that Washington was concerned that the longer the instability dragged on the more likely Iran, a Shiite theocracy, was to try to meddle in Bahrain's affairs.
As tensions rose, Britain and Australia urged citizens to avoid all travel to the country.
"The risk of further outbreaks of violence has increased," the foreign office in London said late Sunday, citing reports that the Saudi National Guard was on its way to the country.
Crown Prince Salman late Sunday reiterated the government's offer of national dialogue on deep-rooted reforms but not at the expense of security and stability, state news agency BNA reported.
In a major concession to the opposition's demands, the prince supported the creation of a parliament with full powers and pledged to tackle corruption and sectarian tensions.
But he warned that "legitimate demands should not be carried out at the price of security and stability."
King Hamad also reiterated an offer of unconditional dialogue with the main opposition groups, which have refused to negotiate until the government resigns.
Foreign Minister Khalid Al-Khalifa, in comments posted in Twitter, accused the opposition of shifting their demands and likened the protesters to gangsters.
"All goodwill gestures were not reciprocated by (protesters)... Look where we are now," he said, adding that protests were "wanton, gangster-style takeover of people's lives."
The mainstream opposition says it is not trying to overthrow the royal family but more radical Shiite elements have said they want a republic.
The United States condemned Sunday's violence, amid claims -- dismissed as lies by the government -- that armed pro-regime thugs are intimidating students and opposition activists.
"We urge the government of Bahrain to pursue a peaceful and meaningful dialogue with the opposition rather than resorting to the use of force," White House spokesman Jay Carney said.