Ahmed Mohamed Nasser al Soofi and Hezam al Murisi were released Wednesday afternoon.
The men were arrested Monday in Amsterdam at the request of U.S. officials after arriving on a United Airlines flight from Chicago.
But by late Tuesday, U.S. officials hadfrom the notion that the men were involved in some sort of rehearsal for a terror plot.
And earlier Wednesday, an attorney for one of the suspects said the suspect was "in shock" at his arrest and has "no connections to terrorist activities whatsoever."
Attorney Wouter Hendrickx said his client Ahmed Mohamed Nasser al Soofi
was on his way to Yemen to visit his family when he was detained.
"He says 'I have no connections to terrorist activities whatsoever,"' Hendrickx told The Associated Press.
Al Soofi was arrested along with another Yemeni, Hezam al Murisi, following a request from U.S. authorities, Dutch prosecutors said.
Both men missed flights to Washington Dulles International Airport from Chicago, and United Airlines then booked them on the same flight to Amsterdam, the U.S. government official said. The men were sitting near each other on the flight, but not together.
Al Soofi also raised suspicions in the United States on Sunday because he was carrying $7,000 in cash. An inspection of his checked luggage uncovered a cell phone taped to a small bottle, multiple cell phones and watches taped together, and a knife and box cutter, according to a U.S. official who had been briefed on the investigation.
None of the checked items violated U.S. security rules, so authorities allowed al Soofi to fly. But his bags later were transferred to another flight and were not on the flight to Amsterdam, Dutch prosecutors said.
Both Al Soofi and Al Murisi changed their travel plans at the last minute and took a direct flight to Amsterdam, raising suspicion among U.S. officials.
However, a U.S. law enforcement official said Tuesday that following FBI inquiries neither man is likely to be charged in America.
Ernst Koelman of the Dutch national prosecutor's office said Wednesday the investigation of the two men was continuing and they could be held without charge until Thursday.
Hendrickx said he has not yet received a case file from prosecutors so he could not discuss further details of the case.
He said the two men were being held in separate cells at a jail in the central Dutch town of Houten.