GUATEMALA CITY, Guatemala (Reuters) - A strong earthquake hit southwestern Guatemala near the border with Mexico in the early hours of Wednesday (June 14), killing one person after a church collapsed and cutting power, officials said.

The 6.9-magnitude quake damaged buildings in the neighbouring southern Mexican state of Chiapas, authorities said, but there were no immediate reports of deaths in Mexico.

"The earthquake was felt throughout the national territory and damage assessment has begun," said Julio Sanchez, spokesman for Guatemala's Conred national disaster centre.

The earthquake hit 15km west-northwest of the city of San Marcos, at around 1.30am local time (0730 GMT) at a relatively deep 111 km, the United States Geological Survey (USGS) reported. The shallower the quake, the more dangerous it could be.

An aftershock struck around 20 minutes later, the agency said.

Power went off in the Guatemalan departments of Retalhuleu, Quetzaltenango and Suchitepequez, authorities said. A church collapsed in San Sebastian, Retalhuleu, killing one person, emergency services reported.

The Civil Protection Authority in Mexico's Chiapas posted photos on Twitter showing damaged buildings and homes.

The USGS initially reported the quake, which struck when many residents were asleep, as a magnitude 7.0.

The Hawaii-based Pacific Tsunami Warning Centre said that based on available data there was no tsunami threat from the quake.

In late 2012, a far shallower 7.4-magnitude quake off the coast of Guatemala near the Mexican border killed at least 48 people and trapped others under rubble.