BANGKOK  A cargo aircraft flying from North Korea and carrying tons of weapons has been seized by Thai authorities during a refueling stop in Bangkok, Thai officials said.

A senior Obama administration official said the United States  which fears North Korea will sell some of its nuclear technology  had tipped off the Thai authorities that the plane, which landed here Friday, might be carrying weapons.

“From our visual inspection there seem to be several types of weapons, components and materials: long tubes, shoulder-fired missiles, certain types of rocket propelled grenades,” Panitan Wattanayagorn, a government spokesman, said in an interview Sunday.

Mr. Panitan said many crates removed from the aircraft had not yet been opened. The full payload was brought to an air force base in central Thailand and will be inspected Tuesday, he said.