China's envoy did not criticise the coup and said the situation was an internal Myanmar affair, adding that China supported a diplomatic effort by southeast Asian countries to find a solution.
Police in Myanmar launched their most sweeping crackdown in three weeks of nationwide protests against military rule on Saturday, arresting hundreds of people and shooting and wounding at least one person.
The coup, which stalled Myanmar's progress toward democracy, has brought hundreds of thousands of protesters onto the streets and drawn condemnation from Western countries, with some imposing limited sanctions.
At the UN General Assembly, Myanmar's Ambassador Kyaw Moe Tun said he was speaking on behalf of Suu Kyi's government and appealed to the body "to use any means necessary to take action against the Myanmar military and to provide safety and security for the people".
"We need... the strongest possible action from the worldwide community to immediately end the military coup, to stop oppressing the innocent people, to return the state power to the people, and to restore the democracy", Kyaw Moe Tun pleaded, his voice cracking with emotion.
The ambassador flashed a three-finger salute that has been adopted by the civil disobedience movement at the end of his speech. The circumstances of the shooting were not clear and police were not immediately available for comment.
Before coup opponents congregated yesterday, about 1,000 supporters of the military turned up at a rally in the city centre in the commercial hub Yangon.
United Nations envoy to Myanmar Christine Schraner Burgener reiterated during the session that the use of lethal force against protesters was "unacceptable".
The National League for Democracy sources said she had been taken away six days ago, the website reported.
One lawyer acting for her, Khin Maung Zaw, told Reuters he had heard the same from NLD officials but could not confirm it. Authorities did not respond to a request for comment.
"It's very important to get her signed power of attorney before the hearing starts on March 1 because we won't be allowed to act as her defence counsels if we can not file (it)", Khing Maung Zaw said. A short time earlier, several people were detained, witnesses said, among them a Japanese journalist, one of his colleagues said.
But groups gathered again in several places to chant slogans and confront riot police who then rushed at them, firing stun grenades and guns into the air to send people scattering.
Similar scenes played out in the second city of Mandalay and several other towns, including Dawei in the south, witnesses and media said.
Aye Aye Tint, a protester in the central town of Monwya said police had fired water cannon as they surrounded a crowd.
Myanmar's crisis took a dramatic turn on Friday when the country's ambassador to the United Nations declared his loyalty to the ousted civilian government of Aung San Suu Kyi during a special session of the General Assembly, and called on the world to pressure the military to cede power.
A man sits in protest against the military coup as riot police stand in formation on a road in a residential area. The army says a policeman was killed in earlier violence.
Facebook said that due to the risks evident from the "deadly violence" seen since the coup it had banned the Myanmar military from using its Facebook and Instagram platforms.
Suu Kyi, the daughter of Myanmar's independence hero, spent almost 15 years under house arrest for her efforts to end military rule.
The Nobel laureate faces two charges for having unregistered walkie-talkies in her residence and for breaking coronavirus rules.
The army has promised a new election but has not set a date.
But Indonesia's intervention has raised suspicion among coup opponents who fear it will confer legitimacy on the junta and its bid to scrap the November vote and arrange a re-run.
ASEAN foreign ministers are planning to hold a meeting on Myanmar next week, regional diplomats said.