Yangon, Myanmar – Myanmar’s government said security forces opened fire Wednesday on demonstrators who failed to disperse, killing one person, and witnesses said police beat and dragged away dozens of Buddhist monks in the most violent crackdown against the protests that began last month in Myanmar.

While dissident groups reported as many as five dead, including monks, the military junta’s announcement on state radio and television was the first acknowledgment that force has been used to suppress the protests and the first admission that blood had been shed. The dissidents also said about 300 monks and activists were arrested.

Responding to calls by world leaders, the United Nations Security Council will hold closed consultations on Myanmar later Wednesday. The session will be briefed by Ibrahim Gambari, the secretary-general’s special envoy on Myanmar, said U.N. deputy spokeswoman Marie Okabe.

Myanmar’s government said the security forces fired after the crowd of 10,000 people, including “so-called monks,” failed to disperse at Yangon’s Sule Pagoda. It said the police used minimum force.

The dead man, aged 30, was apparently hit by a ricocheting shell, the announcement said. It said the wounded, two men and a woman, were not hurt by gunshots but rather from being caught in a melee. Witnesses said they had seen two women and one young man with gunshot wounds in the chaotic confrontations.

Zin Linn, information minister for the Washington-based National Coalition Government of the Union of Burma, which is Myanmar’s self-styled government-in-exile, said at least five monks were killed, while an organization of exiled political activists in Thailand, the National League for Democracy-Liberated Area said three monks had been confirmed dead, and about 17 wounded.

About 300 monks and activists were arrested across Yangon after defying government orders to stay home, according to an exile dissident group, and reporters saw a number of cinnamon-robed monks, who are highly revered in Myanmar, being dragged into military trucks.

“If these stories are accurate, the U.S. is very troubled that the regime would treat the Burmese people this way,” said National Security Council spokesman Gordon Johndroe said in Washington. “We call on the junta to proceed in a peaceful transition to democracy.”

President Bush announced new U.S. sanctions against Myanmar on Tuesday, accusing the military dictatorship of imposing “a 19-year reign of fear” that denies basic freedoms of speech, assembly and worship. Mr. Bush said the U.S. would tighten economic sanctions on leaders of the regime and their financial backers, and impose an expanded visa ban on those responsible for human-rights violations and their families.

British Prime Minister Gordon Brown urged the military regime to be restrained in reacting to protests. “The whole world is now watching,” Mr. Brown said. “I hope the Security Council will meet immediately, meet today and discuss this issue and look at what can be done.”

In Mandalay, Myanmar’s second largest city, more than 800 monks, nuns and laymen played a cat-and-mouse game with some 100 soldiers who tried to stop them marching from the Mahamuni Paya Pagoda, which they had tried to enter earlier. “We are so afraid, the soldiers are ready to fire on civilians at any time,” a man near the pagoda said, asking that his name not be used for fear of reprisals.

The junta had banned all public gatherings of more than five people and imposed a nighttime curfew following eight days of anti-government marches led by monks across the country in the largest protests in nearly 20 years.