(Adds new death toll, revised magnitude)
By Mike McDonald
GUATEMALA CITY, July 7 (Reuters) - A strong earthquake shook the Guatemalan border with Mexico on Monday, killing at least four people, damaging dozens of buildings and triggering landslides.
The 6.9 magnitude quake struck near the frontier, and much of the damage was reported in the Guatemalan border region of San Marcos, where it downed power lines, opened cracks in buildings and triggered landslides which blocked roads.
In November 2012, San Marcos suffered a 7.4 magnitude quake that quake killed 48 people.
Asked to confirm reports the latest quake had claimed three lives in Guatemala, Alejandro Maldonado, director of Guatemalan emergency authority CONRED, said: "Yes, unfortunately."
Emergency services in the Mexican border state of Chiapas said via Twitter that a man died in the town of Huixtla after a wall collapsed on him.
Luis Rivera, governor of the San Marcos region, said at least 48 homes suffered significant damage in the local town of La Reforma, whose municipal cemetery was also destroyed.
"This quake was pretty strong. Families in the area are really scared because of the whole experience of November 2012. There are houses destroyed," he said.
Raul Hernandez, a Guatemalan fire services spokesman, said two deaths were reported in San Rafael Pie de la Cuesta in San Marcos. He also said the quake had damaged 30 houses.
Twelve people are in hospital receiving treatment and 50 houses were evacuated in the region, which suffered major disruptions to communication, added Sergio Vasquez, another spokesman for fire services.
"The whole San Marcos region is pretty affected," he said.
The quake was centered 14 miles (22 km) southwest of the city of Tapachula in Chiapas at a depth of about 37 miles (60 km) said the U.S. Geological Survey, which had originally reported the quake at a magnitude of 7.1.
The quake was also felt in El Salvador. (Reporting by Mike McDonald in Guatemala City and Bill Trott in Washington; Editing by W Simon)