FALFURRIAS, Texas -- More than 40 immigrants smuggled inside two refrigerated truck trailers have been detained after the rigs were searched at a South Texas checkpoint.

A U.S. Customs and Border Protection statement says 19 immigrants were located early Friday at the Falfurrias checkpoint. Border Patrol agents, hours later at the same site, searched another trailer and found 25 more immigrants.

Supervisory Border Patrol Agent Robert Rodriguez on Saturday said both drivers were arrested. Investigators are trying to determine if the smuggling attempts are related.

Temperatures in the trailers were about 45 degrees. Nobody required medical attention.

Rodriguez says the 44 people would be processed according to their immigration status. He declined to release further details on the immigrants from Mexico, El Salvador, Honduras and Guatemala.

The cargo wasn't disclosed.