Authorities say a Border Patrol agent has shot and killed an unarmed man on the banks of the Rio Grande during a struggle.

Authorities say the agent found the man and several others as they carried 260 pounds of marijuana onto the riverbank in Laredo, Texas, from Mexico late Wednesday.

Laredo police say the men scattered when Border Patrol agents approached, but one agent caught a man and the pair struggled before the agent shot him once in the chest.

Laredo police said Friday that investigators don't believe the man was armed. Authorities are working with the Mexican consulate to notify his family before releasing his name.

Border Patrol officials declined Friday to release any information about the agent.