CBP: Border Patrol marine unit shot numerous times

In this file photo, U.S. Border Patrol agents patrol the waters of the Rio Grande Thursday afternoon between the borders of Matamoros, Tamaulipas and Brownsville, Texas. (By Miguel Roberts/The Associated Press)

U.S. Customs and Border Protection says the agents were patrolling on the river near Fronton when they were fired upon by four suspects on the Mexican side of the river.

They say the suspects were all armed with automatic weapons and shot more than 50 rounds at them.

The Border Patrol boat was struck several times but none of the agents aboard were injured.