TAPACHULA, Mexico — A strong earthquake shook the border of Mexico and Guatemala early Sunday, driving frightened residents into the streets.

The temblor struck just before 6 a.m. near the Mexican border town of Suchiate, where a river by the same name divides the two countries. The epicenter was just off the Pacific coast, 10 miles (16 kilometers) west-southwest of Brisas Barra de Suchiate where the river empties into the sea.

The earthquake had a preliminary magnitude of 6.4, according to…