A top US government official said Saturday there was "no chance" the Myanmar junta's planned elections next year would be free and fair.
Myanmar has been in turmoil and its economy paralysed since the February 2021 coup which ousted civilian leader Aung San Suu Kyi.
Suu Kyi's National League for Democracy Party won a landslide victory in November 2020 elections but the military alleged voter fraud to justify the coup.
US State Department counsellor Derek Chollet cast doubt over the junta's pledge to hold new elections in August 2023.
"I think there's no chance it could be free and fair, and it can be an attempt to just manipulate the region, the international community," Chollet told the Shangri-La Dialogue in Singapore.
Almost 2,000 civilians have been killed in the junta's crackdown on dissent and more than 14,000 people have been arrested.
United Nations special envoy for Myanmar Noeleen Heyzer -- who has not been allowed to visit the country since she took up the role late last year -- fears an illegitimate poll could cause further unrest.
She said unless Myanmar citizens had faith the election would lead the country back to "proper civilian rule" and the will of the people would be respected, it could be a "trigger point for greater violence".
Thai foreign ministry representative Pornpimol Kanchanalak however argued the international community should not get "stuck in cancel rhetoric".
"Condemnations, sanctions, ostracisation... have reached diminishing returns," she said.
Pornpimol acknowledged concerns about the upcoming poll but said the international community must take junta's commitment to hold elections "at face value".
The Association of Southeast Asian Nations -- a bloc of 10 countries including Myanmar -- has led stalled diplomatic efforts to resolve the crisis.
Malaysian Foreign Minister Saifuddin Abdullah urged ASEAN countries go back to the drawing board and set deadlines on the "Five-Point Consensus" reached in Jakarta in April 2021, which calls for a cessation of violence and "constructive dialogue".
He said there had been no discussions about booting Myanmar out of the bloc.
Chollet confirmed Washington "was not currently thinking about" supplying weapons to anti-coup fighters in Myanmar despite requests for support like that being given to Ukraine following the Russian invasion.
Post-coup violence has pushed the number of displaced people in Myanmar to more than one million for the first time, the UN said in early June, voicing concerns about a lack of humanitarian assistance as well as the monsoon season.
Since she was ousted, Suu Kyi has been in military custody and faces a raft of charges that could result in her being jailed for more than 150 years.
