On Saturday night, Myanmar's shadow National Unity Government, which coordinates the popular struggle against the junta, said its armed wing, the People's Defense Force will implement a two-week pause in offensive military operations starting on Sunday in earthquake-affected areas.
It said it would "collaborate with the UN and non-governmental organisations to ensure security, transportation, and the establishment of temporary rescue and medical camps," in the areas it controls.
Myanmar's military rulers have let in hundreds of foreign rescue personnel following the deadliest natural disaster to hit the impoverished, war-torn country in years.
Friday's 7.7 magnitude quake, among the biggest to jolt the Southeast Asian nation in the last century, crippled airports, bridges and highways amid a civil war that has wrecked the economy and displaced millions since a military coup in February 2021.
The death toll in Myanmar climbed to 1644, the military government said on Saturday, according to BBC Burmese news service.
Survivors in Mandalay, Myanmar's second-biggest city, dug with their bare hands on Friday in desperate attempts to save those still trapped, lacking heavy machinery and with authorities absent.
In neighbouring Thailand, where the quake rattled buildings and brought down a skyscraper under construction in the capital, Bangkok, at least nine people were killed.
In Bangkok on Saturday, rescue operations continued at the site of the 33-story tower's collapse, where 47 people were missing or trapped under the rubble - including workers from Myanmar.
The US Geological Service's predictive modelling estimated Myanmar's death toll could exceed 10,000 and losses could exceed the country's annual economic output.
A day after making a rare call for international assistance, Myanmar's junta chief, Senior General Min Aung Hlaing, travelled to hard-hit Mandalay near the epicentre of the quake, which brought down buildings and triggered fires in some areas.
An initial assessment by Myanmar's opposition National Unity Government said at least 2900 buildings, 30 roads and seven bridges had been damaged by the quake.
"Due to significant damage, Naypyitaw and Mandalay international airports are temporarily closed," said the NUG, which includes remnants of the elected civilian government ousted by the military coup.
The control tower at the airport in Naypyitaw, Myanmar's purpose-built capital city, collapsed, rendering it inoperable, a person with knowledge of the situation told Reuters.
A Myanmar junta spokesman did not respond to calls seeking comment.
A Chinese rescue team arrived at the airport in Myanmar's commercial capital of Yangon, hundreds of kilometres from Mandalay and Naypyitaw, and will travel up-country by bus, state media said.
Chinese President Xi Jinping spoke by phone with the junta chief, China's embassy in Myanmar said on Saturday, and said Beijing would provide $US13.77 million ($A21.85 million) worth of aid, including tents, blankets and emergency medical kits.
The Association of Southeast Asian Nations, a 10-country bloc that includes Myanmar, said that it recognised the urgent need for humanitarian assistance.
"ASEAN stands ready to support relief and recovery efforts," the group said a statement.
Residents in the hardest-hit areas are desperate for help.
The quake, which hit around lunchtime on Friday, affected wide swathes of Myanmar, from the central plains around Mandalay to the hills of Shan in the east, parts of which are not completely under the junta's control.
Rescue operations in Mandalay could not match the scale of the disaster, one resident said by phone, asking not to be named because of security concerns.
"Many people are trapped but there is no help coming just simply because there isn't manpower or equipment or vehicles," he said.
In Bangkok, 1000 kilometres from the epicentre, authorities on Saturday pushed ahead with efforts to find construction workers trapped under the rubble of the collapsed tower, using excavators, drones and search-and-rescue dogs.
Thailand's Deputy Prime Minister Anutin Charnvirakul said all possible resources had been deployed to search for survivors and to recover the deceased.
"We always have hope," he told reporters.
with AP
