At least four people were killed and as many as 185 brick pagodas were damaged in Bagan after a 6.8 magnitude quake struck the area on Wednesday. The tremor was centred about 25 kilometres (15 miles) west of Chauk, just south of Bagan.
Bagan, also known as Pagan, is one of Myanmar's top tourist attractions, drawing visitors from all over the world who can view a panorama of temples stretching to the horizon flanked by the Irrawaddy River.
Bagan is home to more than 2,200 structures, including pagodas and temples constructed from the 10th to the 14th centuries. Many are in disrepair while others have been restored in recent years, aided by the U.N. cultural agency UNESCO.
On Wednesday, Dr Myo Thant, general secretary of the Myanmar Earthquake Committee, said other areas apparently were not badly affected.
Police officer Htay Win in Pakokku, about 70 kilometres (45 miles) from the epicentre, said one person there had been killed and one injured. "The person was killed by falling bricks from a building," he said.
The Ministry of Social Welfare, Relief and Resettlement reported two other deaths in nearby Thitapwe village.
U.N. spokesman Stephane Dujarric said Secretary-General Ban Ki-moon was "saddened" by the loss of life and damage from the earthquake and expressed his condolences to the "people and government" of Myanmar.
He said the U.N. Office for the Coordination of Humanitarian Affairs was in contact with authorities in Myanmar and along with its partners stands ready to support the government and local organisations.
The last major quake in the area — which is often affected by smaller tremors — occurred in April about 300 kilometres (180 miles) further north, and measured magnitude 6.9. It caused no reported casualties and only minor damage.