Dutch police have detained two men who flew from Chicago to Amsterdam on Sunday night after U.S. screeners found suspicious-looking items in their checked luggage before they departed, U.S. law enforcement officials said.

Security screeners found a cellphone taped to a Pepto-Bismol bottle, three cellphones taped together and a number of watches taped together, prompting American officials to alert the Dutch authorities.

One of the men was also carrying $7,000 in cash.

The men were taken into custody after United Airlines Flight 908 landed at Schiphol Airport on Monday morning.

A law enforcement official, speaking on the condition of anonymity because of the ongoing investigation, identified the men to the Associated Press as Ahmed Mohamed Nasser al-Soofi and Hezam al-Murisi. Soofi had a Michigan address, the official said, but it was not immediately clear where the two men were from.

The law enforcement official said Soofi was questioned as he went through security in Birmingham, Ala., on his way to Chicago. He told Transportation Security Administration authorities he was carrying a lot of cash, the official said, but he was not breaking any law by carrying the $7,000.

Soofi was supposed to fly from Chicago to Washington Dulles International Airport and then on to Amsterdam, the official said. But when he got to Chicago, he changed his travel plans to take a direct flight from there to Amsterdam. Murisi also reportedly changed his travel plans in Chicago to take a direct flight to Amsterdam.

U.S. officials said it was too early to confirm an ABC News report that the men were staging a dry run with "mock bombs" to test the aviation system.

A law enforcement official said the items were not prohibited and there was never a threat to passengers. Federal air marshals were on the flight.

"We don't know yet if these two end up being bad guys or are just really strange people," said one official.