U.S. Border Patrol agents on the American side of the Rio Grande were forced to take cover Friday night when high-caliber weaponry was fired at them from the Mexican side of the river. 

The weapons were fired at the U.S. side of the riverbank in the area of the Rincon Peninsula across the Rio Grande from Reynosa, Mexico, at about 8:30 p.m., sources said. Bullets ricocheted into an area where Border Patrol agents were positioned, Rep. Louie Gohmert, R-Texas, told FoxNews.com. 

Border Patrol sources confirmed Gohmert's account, and said the shots may have been fired by .50-caliber weapons. 

"When the shooting stopped, about 40 to 50 people came out on the U.S. side and turned themselves in. So clearly the rounds were being fired to suppress every effort to stop anybody intervening with anyone or anything coming across," Gohmert added. "We have no idea what or how many or whom came across with the other illegal immigrants."

Sources said they believe the gunfire came from members of Mexican drug cartels, which include former military members trained in shooting that type of weaponry.