Thu Oct 4, 9:04 AM ET

YANGON - Despite gradually easing its iron grip on Myanmar's main city on Thursday, the junta continued to round up scores of people and grill hundreds more arrested during and after a ruthless crackdown on pro-democracy marches.

Although most are too terrified to talk, the monks and civilians slowly being freed from a makeshift interrogation centre in north Yangon are giving a glimpse of the mechanics of the generals' dreaded internal security apparatus.

A relative of three women released said detainees were being divided into four categories: passers-by, those who watched, those who clapped and those who joined in.

"They're looking for the people who led the demonstrations. The people clapping will only get a minimal punishment -- maybe two to five years," said Win Min, who fled to Thailand during a crackdown on a student-led uprising in 1988.

Leaders could be looking at up to 20 years behind bars, he said.

The reports of verbal and physical abuse suggest junta chief Than Shwe is paying scant regard to the calls for restraint delivered by U.N. special envoy Ibrahim Gambari, now flying back to New York to brief his boss, Secretary-General Ban Ki-moon.

"That is one of the top concerns of the international community," said Ban, due to attend a meeting of the 15-member Security Council on Friday to discuss the crackdown in a country now under military rule for an unbroken 45 years.

People in central Yangon's Kamayut district said soldiers had arrested scores of people on Wednesday night for trying to impede a raid on the Aung Nyay Tharzi monastery a few days earlier and giving protection to fleeing Buddhist monks.

Another 70 young monks rounded up in other swoops across the city a week ago were freed overnight from a government technical institute, complementing 80 monks and 149 women believed to be nuns released on Wednesday.

One freed monk, who did not want his name revealed, said some had been beaten when they refused to answer questions about their identity, birthplace, parents and involvement in the protests, the biggest challenge to the junta in nearly 20 years.

"The food and living conditions were horrible," the monk, from Yangon's Pyinya Yamika Maha (A) monastery told Reuters.

Among those detained in the middle of the night on Wednesday was a Myanmar U.N. staff member and her two relatives. They were released, along with her driver, on Thursday, a U.N. source said.

INDIA PROTEST

The junta's crackdown has provoked scores of protests around the world and on Thursday hundreds of Buddhist monks in yellow robes marched in India chanting hymns, and waving placards that read "Stop Killing" and "No violence against democracy."

Dozens of monks from Myanmar, living in the eastern Indian state of Bihar, joined the rally in the holy town of Bodh Gaya, the last resting place of Lord Buddha.

"The Buddhist community is shocked at the way the military rulers fired bullets on monks who were protesting peacefully," said Bhikkhu Bodhipala, chief priest of the Mahabodhi temple in Bodh Gaya.

Gambari was to brief Ban after arriving in New York on Thursday in the midst of international outrage at the use of soldiers against peaceful columns of Buddhist monks and civilians demanding an end to military rule.

Official media say 10 people were killed, including a Japanese video journalist, although Western governments say the final toll is likely to be far higher.

The body of 50-year-old Kenji Nagai, shot dead near Yangon's Sule Pagoda, returned home on Thursday for an autopsy whose results could lead to Tokyo making good on a threat to scale back economic assistance to Myanmar, one of Asia's poorest countries.

Fears of a repeat of 1988, when the army killed an estimated 3,000 people in a crackdown lasting several months, were not realized, but even China, the junta's closest ally, made a rare public call for restraint.

China praised Gambari's mission -- which Western diplomats said Beijing helped facilitate -- saying it gave his efforts a "positive appraisal."