U.S. Border Patrol agents arrested a U.S. citizen and a Mexican national Friday morning for attempting to smuggle at total of 48 undocumented immigrants in two separate incidents.

More: U.S. Border Patrol finds 86 undocumented immigrants near McAllen

Agents assigned to the Sarita checkpoint sent a refrigerated tractor trailer for secondary inspection early Friday morning and found 14 illegal immigrants concealed inside.

A short time later, agents in Falfurrias sent another tractor trailer for secondary inspection after a K-9 unit alerted them to it. This time they found 34 illegal immigrants hidden inside.

Authorities said all subjects were offered medical attention but declined. The drivers of both tractor trailers were arrested.

"In one week alone, we saw four cases at our checkpoints, which clearly demonstrates the disregard for human life that smugglers have," said Chief Patrol Agent Manuel Padilla Jr.

The U.S. Border Patrol encourages citizens to take a stand against crime in their communities and report suspicious activity to 1-800-863-9382.