Kelly Rutherford -- Ordered to Return Kids to Monaco

Kelly Rutherford just lost big in court, and her kids are now on their way to the airport to return to Monaco.

A judge just enforced a court order giving Daniel the right to keep the 2 children in Monaco, while he works out his residency issues with the U.S.

Kelly had refused to return the children after having them for 2 months this summer, arguing the U.S. courts had no authority to order their return. But today a judge disagreed.

We're told Daniel Giersch's mom took the 2 children from the NYC courthouse and they are on their way to the airport to return to Monaco.

There's a hearing on Sept. 3rd in Monaco regarding custody.