The U.S. transportation secretary said Friday that the crew of an ExpressJet aircraft wasn't at fault for a high-profile "passenger stranding," but laid the blame on an official at Mesaba Airlines.

Ray LaHood had called on officials to check whether ExpressJet Holdings Inc. (XJT) and partner Continental Airlines Inc. (CAL) had violated any laws after passengers on a Houston-Minneapolis/St. Paul flight were stuck for six hours in Minnesota following a weather delay.

In a blog entry, LaHood said a preliminary probe showed the ExpressJet crew was "not at fault," and had tried to get the passengers off the plane.

He said a representative of Mesaba Airlines had "improperly refused" requests to allow passengers into the airport in Rochester, MN.

"The Aviation Enforcement Office is considering appropriate action to take against Mesaba as it completes the investigation, which it expects to conclude within a few weeks," said LaHood in his blog.

ExpressJet provides the bulk of regional service for Continental, which also received a letter from LaHood asking what happened to the flight, and what the carrier did to mitigate the delay.

-By Doug Cameron, Dow Jones Newswires; 312-750-4135; doug.cameron@dowjones.com