"We received a report that a child was killed in Tachileik town when a building collapsed because of the quake," said the official, who declined to be named.

Another three people were reported to have been injured in a different part of the town, which was close to the epicenter of the quake, and a resident said he could feel a tremor as he spoke to AFP.

"We have to lie down on the ground. The ward authorities are warning the people through loudspeakers to stay outside the buildings," he said.

"We are really afraid to stay inside our houses tonight."

Aid group World Vision said at least one bridge in the region was reported to have been broken by the quake.

"This part of the country is quite mountainous, and, given last week's severe rains, there are also concerns about landslides following this earthquake," Jenny MacIntyre, communications manager with World Vision in Myanmar, said.

Just across the border from Tachileik in Thailand, police in Mae Sai district said a 52-year-old woman was killed after a wall of her house collapsed.

Colonel Thanomsak Yospan, superintendent of Mae Sai district police, told AFP that the woman's home was poorly constructed and did not stand up to the tremor.

Chiang Rai governor Somchai Hatayatanti confirmed the woman's death and said the aftershock felt in the area was "quite serious".

He said efforts were made to evacuate people from tall buildings and he had ordered all patients from Mae Sai District Hospital to be taken to Chiang Rai.

The quake struck 90 kilometers (60 miles) north of Chiang Rai and 235 kilometers (150 miles) north-north-east of Chiang Mai, Thailand's second city and a popular tourist destination. Tall buildings shuddered in Bangkok during the tremor.

In China, villagers around 40 kilometers from the Myanmar border in the southwestern province of Yunnan said buildings swayed for over a minute during the quake, the official Xinhua news agency reported.

More than 350 students and teachers were evacuated from a school in Menghai County, Yunnan, after the building developed cracks, Xinhua said.

People in the southern Chinese city of Nanning, nearly 900 kilometers (550

miles) from the epicenter, fled buildings when they felt tremors, Xinhua said.

No casualties were reported in China.

In central Hanoi -- in Vietnam, away from the epicenter -- the quake was felt as a smooth rocking motion that lasted for several seconds.

Some Hanoi residents described fleeing their homes in panic.

Nguyen Thi Hong Hanh, 36, who lives on the 10th floor of a highrise, said her husband noticed their pet fish shaking in their tank.

"We all rushed to the street. All the other people in the apartments also rushed out," she said.

Dang Hoang Anh Thu, 36, said her 17th-floor apartment also shook enough to move pictures on the wall.

"We got out, and saw that all other people in the building were heading downstairs as well," the university teacher said.

The city felt the tremor at about magnitude 5.0, according to Dinh Quoc Van, deputy head of the earthquake monitoring department, though there were no immediate reports of damage.

Officials in Myanmar's capital Naypyidaw said they had clearly felt the quake, while a resident of Mandalay in central Myanmar said the shaking lasted for about five seconds.

The quake comes two weeks after Japan was hit by a monster earthquake, which unleashed a devastating tsunami that left around 27,000 people dead or missing and triggered a crisis at its Fukushima nuclear plant.

No tsunami warning was issued after the Myanmar quake as US seismologists said it was too far inland to generate a devastating wave in the Indian Ocean.