YANGON: Police cracked down in Myanmar on Saturday in a bid to prevent opponents of military rule gathering, detaining dozens after the country's U.N. envoy urged the United Nations to use "any means necessary" to stop a Feb. 1 coup.

Myanmar has been in turmoil since the army seized power and detained elected leader Aung San Suu Kyi and much of her party leadership, alleging fraud in a November election her party won in a landslide.

Uncertainty has grown over Suu Kyi's whereabouts, as the independent Myanmar Now website on Friday quoted officials of her National League for Democracy (NLD) party as saying she had been moved this week from house arrest to an undisclosed location.

The coup has brought hundreds of thousands of protesters to Myanmar's streets and drawn condemnation from Western countries, with some imposing limited sanctions.

Police were out in force in the main city of Yangon and elsewhere on Saturday, taking up positions at usual protest sites and detaining people as they congregated, witnesses said. Several media workers were detained.

But people still came out, some for a march by ethnic minorities in Yangon, their numbers building through the day.

Crowds chanted and sang, then scattered into side streets as police advanced, firing tear gas, setting off stun grenades and firing guns into the air, witnesses said.

Similar scenes played out in the second city of Mandalay and several other towns, including Dawei in the south, witnesses and media reported.

A protester in the central town of Monwya said police had fired water cannon as they surrounded a crowd.

"They used water cannon against peaceful protesters - they shouldn't treat people like that," Aye Aye Tint told Reuters from the town.

Among those detained at a Mandalay protest was Win Mya Mya, one of only two Muslim members of parliament for the NLD, media reported.

Junta leader General Min Aung Hlaing has said authorities were using minimal force. Nevertheless, at least three protesters have died in the weeks of turmoil. The army says a policeman was also killed.

'PREVAIL'

At the U.N. General Assembly, Myanmar's Ambassador Kyaw Moe Tun said he was speaking on behalf of Suu Kyi's government and appealed for "any means necessary to take action against the Myanmar military and to provide safety and security for the people".

"We need further strongest possible action from the international community to immediately end the military coup ... and to restore the democracy," he said.

Kyaw Moe Tun appeared emotional as he read the statement on behalf of a group of elected politicians that he said represented the legitimate government.

Delivering his final words in Burmese, the career diplomat raised the three-finger salute of pro-democracy protesters and announced "our cause will prevail".

Reuters was not immediately able to contact the army for comment.

Opponents of the coup hailed Kyaw Moe Tun as a hero and flooded social media with messages of thanks. U.N. Special Rapporteur Tom Andrews said he was overwhelmed as he watched the ambassador's "act of courage".

"It's time for the world to answer that courageous call with action," Andrews said on Twitter.

China's envoy did not criticise the coup and said the situation was Myanmar's "internal affairs". China supported diplomacy by Southeast Asian countries, he said.

But in more bad news for the generals who have traditionally shrugged off outside pressure, Australia's Woodside Petroleum Ltd said it was cutting its presence in Myanmar over concern about rights violations and violence by the security forces.

"Woodside supports the people of Myanmar and we hope to see a peaceful journey to democracy," the company said.

'LOSS OF RIGHTS'

A lawyer acting for Suu Kyi, Khin Maung Zaw, told Reuters he had also heard that she had been moved from her home in the capital, Naypyitaw, but could not confirm it. Authorities did not respond to a request for comment.

The lawyer said he had been given no access to Suu Kyi ahead of her next hearing on Monday and he was concerned about her access to justice and legal counsel.

Nobel Peace laureate Suu Kyi, 75, spent nearly 15 years under house arrest during military rule. She faces charges of illegally importing six walkie-talkie radios and of violating a natural disaster law by breaching coronavirus protocols.

The army has promised an election but not given a date. It has imposed a one-year state of emergency.

The question of an election is at the centre of a diplomatic effort by the Association of Southeast Asian Nations, of which Myanmar is a member.

Indonesia has taken the lead but coup opponents fear the effort could legitimise the junta and what they see as its bid to annul the November election.