300 rounds fired in US shoot-out
Investigators said about 300 rounds were fired during a shoot-out across the Rio Grande between US law enforcement officers and suspected drug runners.
But they said only about six came from the suspects.
Asked about the overwhelming response, US authorities said they have a "zero tolerance" policy when guns are pointed at them.
The Texas Department of Public Safety said it believes three suspects in Mexico were injured or killed in the shoot-out.
The shoot-out started when the US agents spotted a Dodge Durango on US soil.
By the time they reached the scene, the suspected smugglers had moved marijuana from the vehicle onto rafts and returned to Mexico.
They fired guns and threw rocks at US authorities.
Mexican authorities recovered about 400 pounds of marijuana at the site.