The driver drew suspicion at the port's delivery entrance around 8 a.m. after making inconsistent statements, said Judy Orihuela. The driver could not produce the requested paperwork to identify himself and his cargo.

The vehicle was subsequently searched and two additional men were found in the truck's cab, Orihuela said. According to Miami-Dade Police detective Robert Williams, the men were trying to conceal themselves.

The three detainees, all of Middle Eastern descent, were in the country legally and none appear to be on any terrorist watch lists, Oriheula said.

There was no immediate threat to the port, but its cargo area was closed while authorities used an X-ray machine to search the truck, Orihuela said. The Miami-Dade Bomb Squad is checking the vehicle the men were in.

"We want to make sure that trailer was not carrying anything hazardous," Williams said.

The Port of Miami is among the nation's busiest. More than 3.6 million cruise ship passengers traveled through the port in 2005, and its seaport services more than 30 ocean carriers, which delivered more than 1 million cargo containers there in 2005.

The men are currently being questioned by the FBI.