A U.S. Border Patrol agent jumped into the Rio Grande to save a drowning immigrant and returned him to Mexico.

The agency says two Harlingen agents were patroliong west of Progreso on Wednesday morning when they saw two men jump into the water.

They say the teen was in the middle of the river swimming towards Mexico when he started having trouble staying afloat. The second man, the suspected smuggler, ignored the teen and swam away.

According to the Border Patrol one of the agents put on a life preserver and jumped into the Rio Grande. After struggling with the current he was able to reach the boy and carry him to the Mexican side of the river.

He stayed with the teen until he determined he was okay and then swam back to the U.S.

“Human smugglers are callous individuals, who prey upon the desperation of immigrants,” said Chief Patrol Agent Manuel Padilla Jr. “Human smugglers are ruthless individuals who use tactics that place the lives of immigrants and the general public in extreme danger.”

The USBP says it urges immigrants not to swim across the Rio Grande.