YANGON — The government said its security forces opened fire today 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 in a month of protests in Burma.

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.

America and the European Union condemned the attacks and called on the military rulers to open a dialogue with pro-democracy leaders, according to a joint statement on the sidelines of the U.N. General Assembly.

The U.N. Security Council will hold closed consultations on Burma later today, a U.N. deputy spokeswoman, Marie Okabe, said.

About 300 monks and activists were arrested, dissidents said, although that number could not be independently confirmed.

Burma’s leaders had warned the monks to stop the protests after some 100,000 people joined marches in Yangon on Monday in the largest anti-government demonstrations since a 1988 pro-democracy uprising was violently suppressed in the country.

The government said security forces opened fire 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 hit by a bullet, the announcement said.

It said the wounded, two men aged 25 and 27, and a 47-year-old 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.