An international human rights group is calling on the United Nations to respond to attacks by the Burmese government that have chased more than 10,000 villagers from their homes in eastern Burma.  Officials in Thailand say hundreds of displaced Burmese have crossed into Thailand, and thousands more have gathered at the border.

The Human Rights Watch group says more than 10,000 ethnic-Karen villagers have been made homeless by the Burmese military in the past five months.

The group's director for Asia, Brad Adams, says this is the largest offensive by the Burmese government against the Karen minority in nine years.

"They are [the Burmese military] pushing people out of their villages," he says. "They are threatening them with death if they do not leave.  And they are burning villages when people refuse to leave."

Adams notes that the Burmese government often targets Karen civilians out of a belief that they support the Karen National Union, which has been fighting the government for autonomy for decades.

The spokesman for the K.N.U., Colonel Ner Dah Mya, accuses the Burmese government of crimes against humanity.

"The Burmese right now, they are carrying out ethnic cleansing," says Ner Dah Mya. "They burn houses and they kill people.  They use people for forced labor, so people cannot stay."

He says the Burmese military leaders want to remove the Karen from the area around the country's new capital at Pyinmana, 300-kilometers north of Rangoon.

The K.N.U. spokesman said Burmese troops launched mortar attacks against a major rebel stronghold several kilometers from the Thai border.

"This morning in the 7th Brigade area, they started shelling some areas in the frontline area near Mae La," Ner Dah Mya says.

He had no information on casualties, but said he expects the fighting will intensify, driving more refugees to the Thai border.

Adams of Human Rights Watch says the constant attacks by the Burmese military against its own citizens are creating problems for Burma's neighbors, and therefore should be addressed by the international community.

"We want the U.N. Security Council, whether it is under the international threat to peace (measure) or just on the basis of its human-rights mandate, to take up the issue of Burma much more seriously, much more consistently," Adams says.

He accuses Russia and in particular China, which has close ties to the Burmese government, of blocking U.N. action on Burma.

The Burmese government has not commented on the latest offensive.  It says its forces are fighting against what it calls terrorist insurgents who want to divide the country.

Senior Thai officials have confirmed the influx of refugees into Thailand and say they are closely monitoring the situation.

Thailand is home to 140-thousand Burmese refugees, and hundreds of thousands more Burmese who enter the country illegally to look for work.