Thu Sep 27, 11:29 PM ET

YANGON - Security forces swept through Myanmar's main city Thursday, killing nine people including a Japanese journalist, and arresting hundreds more in a brutal crackdown on anti-government protests.

At least 50,000 people, many of them youths and students, swarmed into Yangon undeterred by the deaths the day before of at least four protesters, including three Buddhist monks, and repeatedly defied orders to disperse.

As the shots rang out, they ran for their lives, only to regroup and face down the might of Myanmar's junta which has exerted iron rule over the impoverished country for more than four decades.

Southeast Asian nations demanded Thursday that Myanmar's military junta immediately stop using violence against pro-democracy protestors, as US President George W. Bush urged China to put pressure on the regime to move toward democracy.

As security forces swept through Myanmar's main city Thursday arresting hundreds in a brutal crackdown on the 10th straight day of protests, world outrage mounted while the US slapped sanctions on 14 junta leaders.

In an indication that global pressure was beginning to work, UN leaders were told by Myanmar officials that UN chief Ban Ki-moon's special envoy, Ibrahim Gambari, would be granted a visa to visit the country to assess the situation.

In a previously unannounced meeting, Bush told Chinese Foreign Minister Yang Jiechi he hoped China would use its influence to help bring a peaceful transition to democracy in Myanmar.

Bush also thanked Yang, who was at the White House for talks with US national security adviser Stephen Hadley, for China's help in facilitating Gambari's visit to Myanmar, said US national security spokesman Gordon Johndroe.

In six hours of chaotic protests, state media said nine people were killed and another 11 protesters injured including one woman.

"The protesters threw bricks, sticks and knives at the security forces, so because of the desperate situation the security forces had to fire warning shots," it said, adding 31 police and soldiers were also wounded.

Japanese national Kenji Nagai, 50, a journalist for Tokyo-based video and photo agency APF News, is the first foreign victim of the crackdown.

It was the 10th straight day that large protests have erupted against the ruling junta, which caused outrage in this impoverished Southeast Asian nation by doubling fuel prices on August 15.

British diplomatic sources said there was evidence that monks whose monastery was raided before dawn were "badly beaten", with large amounts of blood found in their dormitories after they were hauled away.

The raid was one of at least three in Yangon's east, which each triggered clashes as hundreds of supporters tried to prevent monks from being hauled away by authorities in an apparent bid to prevent them from leading the protests.

In the city centre, at least 100 other people were taken into custody, thrown into military trucks after troops issued an ultimatum threatening "extreme action" unless they dispersed.

Groups of people were forced to lie on their stomachs while they were searched, and if found with cameras or cellphones -- which are rare in Myanmar -- they were beaten and their equipment was smashed.

State media accused Aung San Suu Kyi's opposition party, the National League for Democracy, of fomenting the unrest by paying people to take part in the protests.

It said that two NLD members, Hla Pe and Myint Thei, had been questioned along with two ethnic party leaders, Htaung Ko Htan and Chin Sian Thang, for their role in the "uprising".

NLD officials said earlier that the two prominent members had been arrested in raids on their homes during the night.

In scenes of naked defiance and anger that the heavy-handed tactics have failed to crush, ordinary people screamed abuse at soldiers and cried openly as they exchanged news of deaths and injuries.

"You are eating food given to you by the people. Yet you kill people and you kill the monks!" an elderly man screamed at the impassive soldiers in Yangon's downtown.

The protests, led by the monks whose revered status had previously made them almost untouchable, have drawn as many as 100,000 people onto the streets in the biggest challenge to the regime for 20 years.

The violence triggered a new round of worldwide condemnation. The United States called the crackdown "outrageous" and tightened sanctions, freezing the assets of Myanmar's military leader and 13 other senior officials.

President George W. Bush met with China's Foreign Minister Yang Jiechi and told him he hoped China would "use its influence in the region to help bring a peaceful transition to democracy in Burma (Myanmar)," said a US spokesman.

Foreign ministers from the Association of Southeast Asian Nations (ASEAN) -- of which Myanmar is a member -- broke with their policy of non-interference in the country's affairs.

"They were appalled to receive reports of automatic weapons being used and demanded that the Myanmar government immediately desist from the use of violence ," Singapore Foreign Minister George Yeo said after a meeting at the United Nations.

The ministers "expressed their revulsion to Myanmar Foreign Minister Nyan Win," he said.

China, Myanmar's biggest trading partner and chief ally, issued its first public call for the regime to show restraint Thursday, but did not directly condemn the crackdown.

The UN said it welcomed news that its special envoy, Ibrahim Gambari, would be allowed to visit Myanmar from Saturday in an attempt to find a way to end the turmoil.

International media rights group Reporters Without Borders said it was shocked at the death of the Japanese journalist.

Thailand-based analyst Win Min, who fled a 1988 crackdown when at least 3,000 people were killed, predicted the movement would grow, saying pictures of security forces attacking monks would fuel anger.

"They also believe that this is the best chance ever since 1988" to bring democracy, he added.