Two men arrested in the Netherlands over concerns they were conducting a test run for a terrorist attack on an airline have been freed without charges.

A statement posted Wednesday on the website of the Dutch national prosecutor's office stated that due to a lack of evidence "there is no reason to hold the men any longer."

At the request of U.S. officials, Dutch security arrested Ahmed Mohamed Nasser al Soofi and Hezam al Murisi, both of Yemeni descent, at Amsterdam's Schiphol Airport on Monday morning after they disembarked a United Airlines flight from Chicago.

However, just a day later, U.S. officials were casting doubt about whether the men were involved in a conspiracy. They said the two, both bound for Yemen, apparently did not know each other.

The men both missed the first leg, from Chicago to Washington, D.C., of their original itineraries, so the airline rebooked them on the direct flight to the Netherlands. They wound up sitting near each other on the plane but not together, a U.S. official has said.

But al Soofi's luggage still went to Washington and was slated to be sent to Dubai. Authorities had earlier found a cellphone taped to a Pepto-Bismol bottle, multiple cellphones and watches taped together, and a knife and box cutter in his checked baggage. The items do not violate U.S. security rules and are "not deemed to be dangerous in and of themselves," according to the U.S. Department of Homeland Security.

However, because the man and his unusual luggage were headed to separate international destinations, U.S. authorities alerted their Dutch counterparts over security concerns.

With files from The Associated Press