But the United States was less optimistic about the situation, vowing continued pressure to ensure a 'substantive dialogue' with the democratic opposition in Myanmar.

Professor Gambari told the 15-member council yesterday that his six-day mission to Myanmar last week had led to some 'positive outcomes'.

These include the military regime's decision to lift curfews imposed during September's anti-government protests, the release of more than 2,700 detainees and political prisoners and the talks between opposition leader Aung San Suu Kyi and Labour Minister Aung Kyi.

'On balance, the positive outcomes of this latest mission show that the government of Myanmar can be responsive to the concerns of the international community,' Prof Gambari said.

But he conceded that the regime 'has yet to provide any assurance that it will lift restrictions on Aung San Suu Kyi', and cited 'serious concerns about ongoing reports of human rights abuses and the willingness of the government to move forward in a new direction'.

Several council members praised Prof Gambari for his efforts, but the US and its Western allies said Myanmar's rulers must do more, including allowing the UN envoy to return soon and have full access to all those he needs to see.

'He's doing a good job. His latest mission had some success,' US ambassador to the UN Zalmay Khalilzad said of the world body's troubleshooter.

'But we believe there's a need for further substantive progress and the ball is in the court of the government.'

Mr Khalilzad made it clear he was not ruling out further unilateral or multilateral sanctions if necessary.

Meanwhile, UN human rights envoy Paulo Sergio Pinheiro, who is in Myanmar to investigate allegations of widespread human rights abuses, says he is disturbed by the arrest of prominent labour activist Su Su Nway.

Su Su Nway, who had been on the run for more than two months, was arrested on Tuesday morning in Yangon as she tried to place a leaflet near a hotel where Mr Pinheiro was staying, said exiled Myanmar dissidents in Thailand.

Mr Pinheiro plans to raise the issue of her arrest in his meetings with government officials before ending his visit today.

The authorities have also arrested four more people, including a Buddhist monk who was a key leader of the massive anti-junta protests in September, according to reports yesterday.

'U Gambira was arrested on Nov 4,' said Aung Kyaw Oo, who works for the Thailand-based monitoring group Assistance Association for Political Prisoners.

'We can't exactly say (where he is now), but I think he is in an interrogation centre,' he said.

The junta had placed U Gambira on its wanted list, announcing on state television early last month that he was one of four monks it was hunting down for leading the protests.

The other three people arrested were handing out anti-regime pamphlets at the busy Thiri Mingalar fruit and vegetable market in Yangon, shoppers and other witnesses said yesterday.

'I saw at least three young men in white shirts being arrested by market security officials,' said one of the witnesses, a market worker.

REUTERS, AGENCE FRANCE-PRESSE