HOUSTON, Sept. 6 (Xinhua) -- The U.S. federal officials are investigating a shooting incident involving a U.S. agent who allegedly fired his weapon across the U.S.-Mexico border and killed a Mexican citizen, a U.S. official said Thursday.
U.S. Border Patrol spokesman Bill Brooks said Thursday that a group of people threw rocks at U.S. agents aboard a boat near Laredo, Texas, on Monday, and that an agent opened fire toward the Mexican city of Nuevo Laredo across the border.
Brooks said it was not yet clear if anyone was hit by the bullets, according to daily newspaper Houston Chronicle.
The Federal Bureau of Investigation (FBI) is investigating the rock-throwing as an attack on federal officers and the shooting will be investigated as an internal review by the Border Patrol, FBI spokesman Erick Vasys was quoted as saying.
Tensions have flared again at the border between the U.S. and Mexico, after a Border Patrol agent allegedly shot and killed a Mexican citizen at a park along Rio Grande, which splits the border towns of Laredo, Texas, and Nuevo Laredo.
The Border Patrol agent riding in a boat on the Rio Grande shot the Mexican resident twice, once in the chest and once in the leg, according to the Laredo Morning Times. His family said he was at the park grilling fajitas. The Mexican died in hospital.
The Border Patrol, however, said the agent fired because his unit was "subjected to rocks being thrown at them from the Mexican side of the Rio Grande."
Mexico's Foreign Relations Department said in a statement Wednesday that the Mexican government strongly protested the shooting, and reiterated its objection to the use of force by Border Patrol agents.
It's not the first time that a killing at the border has caused tension along the U.S.-Mexico border.
The Border Patrol shot and killed a Mexican citizen in July and another Mexican in 2010. Both shootings drew strong criticism from the Mexican government, which accused the Border Patrol of using excessive force against Mexican citizens.