YANGON - Burma's junta staged a massive pro-government rally in its main city on Saturday and arrested a top dissident as its relentless and ruthless response to last month's pro-democracy uprising showed no signs of easing.

Htay Kywe, a prominent student activist from an uprising in 1988, was detained overnight with three other people in one of the many raids still being conducted by police more than two weeks after soldiers were sent in to crush demonstrations.

The 39-year-old, a leading light in the so-called "88 Generation Students Group", had managed to remain at large since 13 of his comrades were arrested in a series of midnight swoops on Aug. 21.

"They had felt the net closing in for several days," a close friend, now in exile, told Reuters in Bangkok.

Despite some concessions to the international outrage at the crackdown, in which at least 10 people died, the former Burma's ruling generals are cranking up the pressure on the domestic front.

After three weeks of provincial pro-government "rallies" -- turgid, stage-managed affairs at which attendance is compulsory -- the junta brought its roadshow to a sports ground in Yangon, the main city and former capital.

Tens of thousands of people from government organisations, private factories and nearby suburbs sat through drizzle to voice choreographed support for the junta's "roadmap to democracy" and a constitution-drafting National Convention.

"The delegates just read out everything written by the authorities," one attendee told Reuters. "It was the usual stuff -- support the National Convention and condemn the so-called 'destructive elements'."

In junta-speak, 'destructive elements' means anybody wanting to bring an end to 45 years of military rule and economic stagnation in a country that ranked as one of Asia's brightest prospects shortly after independence from Britain in 1948.

UN ENVOY RETURNS

United Nations special envoy Ibrahim Gambari is flying back to Asia this weekend to brief regional governments, and hopes to wind up his trip with another visit to Burma before the end of the month.

On his last trip, Gambari was given a rare audience with Senior General Than Shwe as well as two short meetings with detained opposition leader and Nobel laureate Aung San Suu Kyi.

The junta has also appointed a big-hitting minister to act as a go-between with Suu Kyi -- whom Than Shwe is widely know to loathe -- raising hopes that the generals might be contemplating serious talks and possible democratic reform.

However, the tone of its response to an unprecedented rebuke this week from the U.N. Security Council, which "strongly deplored" the military crackdown against Buddhist monks and civilians, suggests otherwise.

Official media described the council's statement as "regrettable" and said it was "totally disregarding the fact that the situation in Burma does not represent a threat to the regional and international peace and security".

Despite the strong words at the U.N., veto-wielder China has made it clear it will not allow any formal action such as sanctions to be taken against Burma, where Beijing is lining up deals to buy huge reserves of natural gas.

India, another energy-hungry regional giant, is equally reluctant to act, and the army-appointed government in Thailand, which buys $2 billion of Burma gas each year -- also said it would not be taking any concrete measures against its neighbour.

"As a Buddhist country, we disagreed with the violence dealt out by the Burma government, especially against the monks," Prime Minister Surayud Chulanont said in a weekly television address on Saturday.

"But if we do anything that will cause bad feelings with our neighbour, that will be problematic for the new elected government," he said. "I think we could pressure them more if we are not an appointed government."