SAN DIEGO -- An immigration sweep that resulted in the arrests of dozens of illegal immigrants took place in the most unexpected of places, and immigration rights activists are unhappy with the operation, 10News reported.

The sweep, which happened Wednesday at the Old Town transit center, involved agents from the Transportation Security Administration and the Border Patrol.

A Border Patrol spokesman denied the use of racial profiling. He said behavior detection officers helped identify suspected illegal immigrants on board the trolley.

While some questioned the legality of conducting a sweep on a trolley, a TSA representative said they have conducted more than 1,000 similar sweeps on a variety of modes of transportation, and federal law said it is legal.