Sat Sep 29, 11:44 AM ET

YANGON - A UN special envoy arrived in Myanmar on Saturday for talks with the ruling junta, which has locked down the nation's biggest city in a violent campaign to choke off mass demonstrations.

The United States has called on Myanmar's generals to also allow Ibrahim Gambari to meet with opposition leader Aung San Suu Kyi, the democracy icon who has been held under house arrest for most of the past 18 years.

UN chief Ban Ki-moon dispatched the Nigerian-born Gambari to broker negotiations between the isolated military regime and its pro-democracy opponents, who have mounted two weeks of nationwide mass rallies.

A violent crackdown to end the demonstrations -- which has claimed at least 13 lives since Wednesday -- appeared to have largely succeeded in deterring anti-government campaigners from returning to the streets.

In two clashes Saturday, troops beat and dispersed protesters in Yangon, but for the most part the country's largest city was eerily quiet with security forces outnumbering demonstrators and locking down Buddhist monasteries.

At Bogyoke Aung San market, a major tourist destination also known as Scott's Market, warning shots were fired to disperse about 500 anti-government demonstrators, and an unknown number were arrested, witnesses said.

Nearby at the Pansoedan bridge, another 100 protesters gathered, but when they started to clap their hands a squad of about 50 security forces baton-charged them and arrested about five, witnesses said.

"They beat people so badly," said one Yangon resident who witnessed the scene. "I wonder how these people can bear it."

The crackdown, in which hundreds have been arrested, had already succeeded in reducing the intensity of the protests Friday, when only about 10,000 turned out in Yangon compared with up to 100,000 at the height of the rallies.

However, in the central city of Pakokku, witnesses said that Buddhist monks led thousands of protesters Saturday in a peaceful two-hour march which appeared to have been mounted with the approval of local authorities.

"About 1,000 monks led the protest, and they were followed by more people on bicycles and motorbikes," said a witness.

The recent wave of protests has been Myanmar's biggest since an uprising in 1988 that ended with troops killing some 3,000 people, and the regime's bloody response this week has drawn outrage from around the world.

The UN's Gambari said en route to Myanmar that he was looking forward to "a very fruitful visit" and expected to "meet all the people that I need to meet."

After arriving in Yangon he flew straight to the new capital of Naypyidaw where he was expected to meet with regime leader Senior General Than Shwe.

Myanmar's secretive generals last year shifted the capital from Yangon to Naypyidaw, 450 kilometres (250 miles) to the north, in a move observers believe may have been driven by astrologers' advice or fears of a US military attack.

Gambari has visited Myanmar twice before, and on one occasion was allowed to see opposition leader Aung San Suu Kyi, a Nobel Peace Prize laureate who last week was able to briefly meet protesting monks.

The monks who initially led the protests were nowhere to be seen in Yangon after a brutal campaign of arrests, bashings and monastery raids which has shocked the country.

Troops have blockaded many big monasteries, including those in the religious capital of Mandalay in central Myanmar, and monks are only allowed to move around in small groups.

A Western diplomat based in Yangon said Saturday there were reports of divisions within the military on how to handle the crisis in Mandalay, home to the majority of Myanmar's 400,000 monks.

On Friday, diplomats said they had received information from several sources about "acts of insubordination" within the army and that some soldiers were willing to take the side of demonstrators.

The World Food Programme, meanwhile, said the bloody crackdown has hampered efforts to distribute food to 500,000 vulnerable people, mostly children, and appealed to the junta "for access to all parts of the country."

Myanmar's main Internet connection, cut Friday, remained off Saturday, severely reducing the flow of video, photos and first-hand reports of the violence, which helped inform the world of the crisis in the isolated nation.