Aid groups in the worst-hit areas of Myanmar said there was an urgent need for shelter, food and water after an earthquake that killed more than 2,700 people, but said the country's civil war could prevent help reaching those in need.

The death toll had reached 2,719 and is expected to rise to more than 3,000, Myanmar's military leader Min Aung Hlaing said in a televised address on Tuesday. He said 4,521 people were injured, and 441 were missing.

The 7.7 magnitude quake, which hit around lunchtime on Friday, was the strongest to hit the Southeast Asian country in more than a century, toppling ancient pagodas and modern buildings alike.

WATCH | Crews continue search for signs of life in Myanmar, Thailand after earthquake: 

Crews look for signs of life after Myanmar-Thailand earthquake

A crucial window to find survivors of the devastating earthquake in Myanmar and Thailand has closed, but crews continue to search for any signs of life in the rubble as families hope for a miracle.

In Myanmar's Mandalay area, 50 children and two teachers were killed when their preschool collapsed, the United Nations Office for the Coordination of Humanitarian Affairs said.

"In the hardest-hit areas ... communities struggle to meet their basic needs, such as access to clean water and sanitation, while emergency teams work tirelessly to locate survivors and provide life-saving aid," the UN body said in a report.

The International Rescue Committee said shelter, food, water and medical help were all needed in places such as Mandalay, near the epicentre of the quake.

"Having lived through the terror of the earthquake, people now fear aftershocks and are sleeping outside on roads or in open fields," an IRC worker in Mandalay said in a report.

U.S. reponse hobbled, ex-official says

The U.S. State Department on Monday said that a U.S. Agency for International Development team (USAID) was heading to Myanmar to help identify the country's most pressing needs but a former top USAID official said the overall response from Donald Trump's administration response has been hobbled by the huge fund cuts, contractor terminations and plans to fire nearly all staff.

The response has been hurt by "a lot of internal confusion about capability to respond and willingness to respond," said Sarah Charles, who headed the agency's humanitarian assistance bureau until February 2024. 

Speaking at a daily briefing, State Department spokesperson Tammy Bruce rejected criticism that funding and personnel cuts were impeding USAID's response and said that Washington was working with partners in Myanmar to get help to affected people.

Trump, through an initiative led by billionaire adviser Elon Musk, in February began the process of closing USAID and merging its operations into the State Department. Thousands of staff were placed on administrative leave, hundreds of contractors were fired and more than 5,000 programs terminated, disrupting global humanitarian aid efforts on which millions depend.

On Friday, the day the earthquake struck Myanmar and Thailand, the administration told Congress that it was firing nearly all remaining USAID personnel and closing its foreign missions.

The processes that trigger rapid USAID disaster responses "that were pretty automatic" no longer are, and the "process of getting approval to do things, the process of deploying people, is all being negotiated in real time," said Charles.

According to Human Rights Myanmar, an aid group, the U.S. accounted for a quarter of all aid to Myanmar before Trump was inaugurated, and U.S. assistance was seen as crucial for the Rohingya refugees who fled the country and languish in camps in Thailand and Bangladesh.

Military rule a complicating factor

The civil war in Myanmar, where the junta seized power in a coup in 2021, has complicated efforts to reach those injured and made homeless by the Southeast Asian nation's biggest quake in a century.

Amnesty International said the junta needed to allow aid to reach areas of the country not under its control. Rebel groups say the junta has conducted airstrikes after the quake.

"Myanmar's military has a longstanding practice of denying aid to areas where groups who resist it are active," Amnesty's Myanmar researcher Joe Freeman said.

"It must immediately allow unimpeded access to all humanitarian organizations and remove administrative barriers delaying needs assessments."

The junta's tight control over communication networks and the damage to roads, bridges and other infrastructure caused by the quakes have intensified the challenges for aid workers.

Thai officials said a meeting of regional leaders in Bangkok later this week would go ahead as planned, although the junta's leader may attend by teleconference.

Before the quake struck, sources said the junta chief had been expected to make a rare foreign trip to attend the summit in Bangkok on April 3-4.

Hopes dim at collapsed Thai building

In neighbouring Thailand, rescuers were still scouring the ruins of an unfinished skyscraper that collapsed for any signs of life, but aware that as four days had passed since the quake, the odds of finding survivors lengthened.

"There are about 70 bodies underneath ... and we hope by some miracle one or two are still alive," volunteer rescue leader Bin Bunluerit said at the building site.

Bangkok Deputy Gov.Tavida Kamolvej said six human-shaped figures had been detected by scanners, but there was no movement or vital signs. Local and international experts were now working out how to safely reach them, she said.

Search and rescue efforts continued at the site, as family and friends said they feared the worst.

"The rescue teams are doing their best. I can see that," said 19-year-old Artithap Lalod, who was waiting for news of his brother.

"However it turns out, that's how it has to be. We just have to accept that things will be the way they are," he said.

Thirteen deaths have been confirmed at the building site, with 74 people still missing. Thailand's national death toll from the quake stands at 20.