"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.
미얀마서 7.0 강진..최소 11명 사망
미얀마 동북부에서 24일 리히터 규모 7.0의 강진이 발생해 최소한 11명이 목숨을 잃었다.
미국 지질조사국(USGS)에 따르면 지진은 오후 8시25분(한국시각 10시55분) 태국 과 라오스 국경에 가까운 미얀마 산악지역의 불과 지하 10km 지점에서 일어났다.
진앙은 태국 치앙라이 북쪽 90km, 제2 도시이자 관광명소인 치앙라이 북북동 23 5km 지점이다.
미얀마 소식통들은 켕퉁주를 강타한 이번 지진으로 인접한 동북부 샨주의 타치 레이크와 타르핀에서 산사태와 건물붕괴로 적어도 10명이 숨졌다고 밝혔다.
또한 미얀마 국경에서 4km 떨어진 치앙라이의 북부 지역에서 여자 1명이 벽돌담이 무너지면서 깔려 사망했다고 현지 경찰이 전했다.
앞서 외신들은 규모 7.0 강진이 수초 간격으로 두 차례 발생했다고 타전한 바 있다. 일부 외신은 지진의 규모를 6.8이라고 전했다.
이번 지진으로 방콕과 베트남 수도 하노이 등지에서도 강력한 진동이 느껴졌다.
지진은 내륙 깊숙한 곳에서 일어나 인도양에 쓰나미를 일으키지는 못한 것으로 나타나 쓰나미 경보는 발령되지 않았다. (연합뉴스)