TRIPOLI/MANAMA (Reuters) – Security forces in the Libyan city of Benghazi killed dozens of people as they fought to crush an uprising against leader Muammar Gaddafi's rule, the bloodiest of multiple revolts now rocking the Arab world.

Witnesses said Benghazi was in a state of chaos, with government buildings ransacked and troops and police forced to retreat to a fortified compound, from where snipers picked off demonstrators.
In the Gulf kingdom of Bahrain, thousands of anti-government protesters camped over Saturday night in a Manama square. But after days of violence in the Sunni-ruled island state, the mood appeared to be more conciliatory with talks due to take place on Sunday between the opposition and the crown prince.

Unrest also hit Yemen, Morocco, Oman, Kuwait, Algeria and Djibouti over the weekend as people took to the streets demanding political and economic change. Authorities in Saudi Arabia detained activists trying to set up the kingdom's first political party.

The clamor for reform across a region of huge strategic importance to the West and the source of much of its oil began in Tunisia in December. The overthrow of President Zine al-Abidine Ben Ali then inspired Egyptians to rise up against strongman Hosni Mubarak, sending him packing on February 11.

The tide has challenged leaders of countries long backed by the West as well as erstwhile enemies. While each has its own dynamics, from religion to tribalism, all seem united by frustration over economic hardship and a lack of political freedom.

BLOODSHED IN BENGHAZI

In Libya, Gaddafi responded to the biggest challenge of his four decades in power with ruthless force. New York-based Human Rights Watch said security forces had shot dead at least 104 people, based on interviews with witnesses and hospital officials.

"We are in the midst of a massacre here," a witness told Reuters in Benghazi.
The situation was confused as the Libyan government has restricted media access and blocked some communications, including the Internet.

However, protesters appeared to have taken over much of Benghazi and security forces had retreated a fortified compound in the town center, from where snipers were shooting at people.
"Right now, the only military presence in Benghazi is confined to the Command Center Complex in the city. The rest of the city is liberated," one witness said late on Saturday.

"Thousands and thousands of people have gathered in front of Benghazi's court house. All the (local government) offices and police stations in the city have been burned."

Benghazi and the surrounding area have been the focus of the Libyan unrest. But posts on social network sites, which could not be verified, referred to minor clashes in the capital Tripoli and of overnight gunfire in Nalut, to the west.

Nonetheless, Libya watchers said an Egyptian-style nationwide revolt was unlikely as regional grievances were a factor in the unrest.

Gaddafi traditionally has less support in the east than in the rest of the country, where he is respected by many despite the lack of Western-style democracy. And Libya's oil wealth allows him to spread largesse to smooth over social problems.

PRINCE AND PROTESTERS

In Bahrain, Crown Prince Sheikh Salman bin Hamad al-Khalifa, who is emerging as a leading player among the ruling elite, made conciliatory noises after days of unrest that left six dead.
"All political parties in the country deserve a voice at the table," Crown Prince Salman told CNN before talks with the opposition.

"I think there is a lot of anger, a lot of sadness ... We are terribly sorry and this is a terrible tragedy for our nation," said the prince, who is seen as a reformist.

Speculation was growing that Prime Minister Sheikh Khalifa bin Salman al-Khalifa will be replaced by the crown prince, who has pushed aside for now the hawks in the royal court.

On the crown prince's orders, troops and armored vehicles withdrew from Pearl Square on Saturday, which they had taken over on Thursday after riot police staged a night-time attack on protesters.
People streamed back toward the square early on Sunday to push opposition demands for the resignation of the government and talks on a new constitution.

On Saturday, the crown prince suggested the unrest was the result of a lack of action on demands by Shi'ites who make up 70 percent of the population of the kingdom, which is ruled by a Sunni Muslim family.
He told Al Arabiya television there might be a feeling that some basic demands had not been met. "We want to correct this situation and prevent its repetition."

Shi'ites have long complained of unfair treatment in access to state jobs and housing in Bahrain, a close ally of Saudi Arabia and the United States, whose Fifth Fleet is based there and projects U.S. military power in the Middle East and Central Asia.

Oil giant Saudi Arabia, which fears unrest may spread to its own Shi'ite minority, said it was following developments in Bahrain with interest and hoped for the return of peace and stability.

In Tunisia on Sunday, security forces fired into the air as tens of thousands of demonstrators gathered downtown to call for the replacement of the interim government -- a sign that problems are not all swept away with the removal of a dictator.

Following weeks of relative calm, as many as 30,000 marchers gathered in front of the prime minister's building shouting slogans such as "We don't want the friends of Ben Ali!."

In Yemen, supporters of President Ali Abdullah Saleh tried to break up a demonstration in Sanaa by opponents of the government and shots were fired as unrest in the country entered its ninth straight day.
At least 2,000 protesters gathered in a square in Morocco's capital on Sunday to demand that King Mohammed give up some of his powers and clamp down on government corruption.

(Reporting by Reuters bureaus; Writing by Angus MacSwan; editing by David Stamp)