YANGON — Four prominent political activists were arrested in Burma yesterday as the ruling junta kept up its crackdown on pro-democracy protesters, Amnesty International said.

Activists Htay Kywe, Aung Htoo, and Thin Thin Aye, also known as Mie Mie — were members of the 88 Generation Students’ Group of student leaders active in a 1988 pro-democracy uprising, Amnesty said. It said a fourth activist, Ko Ko, was also arrested.

The London-based rights group said that it did not have details of the arrests, which could not be independently confirmed, but that it feared for the activists’ safety.

“Amnesty International believes that these high-profile opposition figures are at grave risk of torture and mistreatment,” the rights group said in a statement.

Meanwhile, thousands at a government-staged mass rally in Yangon shouted slogans against Western powers and the foreign media, whom the military regime accuses of fomenting recent pro-democracy protests.

“Down with BBC! Down with VOA! Down with Radio Free Asia!” the crowds chanted at the rally, held amid growing international pressure on the junta to negotiate with the opposition. Many in the crowd were offered cash to attend, local officials said.

People bused in from other parts of the city gathered at a sports ground for the rally, which officials said 120,000 attended.

Local officials said on condition of anonymity that they had been ordered by the government to round up delegations from various parts of the city to attend, offering some of them payments of about 80 cents a person.

The United Nations has been spearheading an international effort to push the military, which has ruled Burma since 1962, to enter negotiations with opposition leader Aung San Suu Kyi and move toward democratic reforms.