Two Men on a United Airlines flight from Chicago were detained today when the plane arrived in the Netherlands.

U.S. officials say luggage belonging to one of the men contained what appeared to be mock bombs - and they may have been testing the security system.

CBS News Justice correspondent Bob Orr reports U.S. officials are still trying to figure out whether or not this is a real threat. But, it is suspicious. Two men who flew from Chicago to Amsterdam have now been arrested in the Netherlands.

Sources say one of the men, Ahmed Mohammed Nasser al-Soofi, a 48-year-old Yemnini who has permanent resident status in the United States, had $7,000 in cash and what looked like mock explosive devices in two checked bags, seven cell phones - some of them we're told were taped to empty bottles - and watches taped to shampoo bottles. Al-Soofi, who resides in Detroit, was singled out for a pat down at Birmingham International Airport in Ala. on Sun. His checked baggage had set off an alarm as it was screened. He was allowed to continue on a flight to Chicago O'Hare.

Officials say al-Soofi, who originally was heading through Dulles to Yemen had changed his itinerary to the Amsterdam flight. The two bags carrying those suspicious items did not go with the man on the flight to Amsterdam. Instead, the two bags continued on al-Soofi's original path to Dulles Airport near Washington - where they were confiscated by U.S. authorities.

The other man arrested, Hazem Abdullah Thabi al-Murisi, is a 37-year-old Yemini who traveled to the United States on a vistor's visa.

While two men have been arrested, authorities now say they are not linked to one another. The investigation is focused solely on al-Soofi. Al-Murisi was also supposed to land in Dulles, but changed his flight in Chicago to Amsterdam.

Investigators say this does not appear to be connected to any terror threat -but authorities do want to know if al-Soofi was testing security.

These were amateurish-like mock devices - the very kind of thing that security is designed to find. And in fact, TSA did find them on the flight from Birmingham to Chicago and deemed them benign. That's why they were allowed to go to Chicago and then on.

Homeland Security spokeswoman Amy Kudwa said once officials found suspicious items in luggage associated with two passengers on Sunday night's flight, they notified the Dutch authorities.

Kudwa said none of the items found were considered dangerous "in and of themselves."