A series of powerful aftershocks rattled nerves after Sunday's 6.8-magnitude quake, which sent terrified people running from their homes in Myanmar's second-biggest city of Mandalay and surrounding villages.
Authorities said they were providing help to victims including those without shelter after more than one hundred homes were damaged but that communication problems made it difficult to assess the scale of damage and reach more remote areas.
Villagers in settlements north of Mandalay told AFP Monday they had yet to see rescue teams following the quake, which left dozens injured and also damaged monasteries and public buildings.
"I have never felt such a big earthquake in my life. Everybody is terrified," said Win Tint, the head of Khu Lel village near Sint Ku township.
Local people had tried to salvage Buddha statues from a damaged monastery but fled in panic when aftershocks began, he said.
Some 40 buildings in the village were damaged in the quake and while there had been no serious injuries in the village, residents had been forced into temporary shelters set up in the fields.
"The situation is quite bad. No rescue team has arrived here so far," he said.
Following the initial jolt, which was felt as far away as the Thai capital Bangkok, the US Geological Survey (USGS) recorded two further strong quakes of 5.8 and 5.6-magnitude.
A United Nations Office for the Coordination of Humanitarian Affairs (OCHA) report Sunday said government departments had indicated "significant damage to houses, infrastructure and public buildings, including primary and secondary schools, monasteries and pagodas in various locations".
At least 100 homes were said to be damaged in two townships, it said, adding the government's Relief and Resettlement Department had responded by providing tents.
OCHA said Myanmar government reports suggested seven people had been killed, four were missing and dozens injured in the quake.
The UN's chief in Yangon, Ashok Nigam, said stocks of relief aid were stretched, given the ongoing humanitarian crisis in Rakhine state in western Myanmar where communal unrest has forced more than 110,000 people to flee their homes.
"Depending upon what response is required, we will have to assess at that point... but yes, we do have a very intense emergency going on in Rakhine and the stocks are low," he told AFP.
A situation report from Save the Children on Sunday put the number killed at 13, including four labourers who plunged into the Irrawaddy River near Sint Ku when the steel structure of a large, partially built bridge collapsed.
Six more people were killed in Sint Ku township, including two who died when a gold mine caved in. Damage to a monastery in the nearby village of Kyauk Myaung left two people dead and a further fatality was reported in Mandalay, it said.
Residents in Mandalay fled shaking homes and hotels in panic, but no major damage was reported in the city. Construction standards are generally poor in the country formerly known as Burma, one of Asia's most impoverished nations.
The quake comes little more than a week before US President Barack Obama is due in Myanmar on a historic visit, as the West rolls back sanctions to reward dramatic reforms under President Thein Sein.
More than 70 people were killed in March 2011 when a powerful 6.8-magnitude quake struck Myanmar near its borders with Thailand and Laos.
Aid workers praised the country's regime for its speedy response to that quake, in contrast to the handling of previous natural disasters by the junta which had ruled the country for decades.