(AP) -- BROWNSVILLE, Texas (AP) -- The U.S. Border Patrol said an agent fired shots after being pelted by rocks thrown along the border.

Border Patrol spokesman Henry Mendiola said Saturday he did not know if anyone was struck by the gunfire.

He said the shooting about 9 a.m. in Brownsville happened when an agent "feared for his life" and fired his weapon.

Mendiola said the investigation is still very preliminary and he could not release any more details.

In 2010, a Border Patrol agent in El Paso shot and killed a 15-year-old Mexican boy across the Rio Grande.

Investigators said the agent fired after being attacked by people throwing rocks.

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