BOGOTA, Oct 27 - Venezuela on Monday denied a plane permission to land to recover the bodies of eight slain Colombians, in a move Foreign Ministry officials in Bogota described as "extremely serious."

The people killed were among a dozen kidnapped during a soccer match in the Venezuelan town of Fernandez Feo, in Tachira state.

The standoff over the right to land the Colombian plane on Venezuelan soil was the latest development in ongoing tense relations between the Andean neighbors.

"We fail to understand the reason for the refusal, but it is an extremely serious act," a Colombian Foreign Ministry official told AFP.

"The Venezuelan Foreign Ministry notified our ambassador that the plane that was to have recovered the bodies of the massacred Colombians would not be allowed to land."

The Venezuelan Embassy in Bogota later said permission to land was denied because Venezuela was already preparing to deliver the bodies, as Colombia's consul in San Cristobal, Venezuela, had requested on Saturday.

"The transfer operation was already under way," an embassy statement said.

A Colombian Foreign Ministry official confirmed that Venezuela on Saturday began providing the "logistical and material support... for a land transfer to the city of Cucuta," in northeastern Colombia.

In turn, the official added, Colombia requested the coordinates of the Venezuelan operation -- presumably to expedite the bodies' transfer by plane.

Bilateral relations soured anew on Sunday when Venezuelan President Hugo Chavez berated Colombia's Defense Minister Gabriel Silva as a "mental retard" who was beholden to orders from the United States government in the wake of a US deal to use seven Colombian military bases.

"The Colombian defense minister -- this mentally feeble, if not mentally retarded guy -- takes order from the empire," said Chavez, using one of his favorite epithets for the United States during his "Hello, Mr President" weekly broadcast.

The Colombian diplomatic official said Bogota was reviewing its options, including the possibility of traveling via land to recover the bodies from the site near the Venezuelan border.

The Venezuelan Embassy said Caracas security forces were "working intensely to clear up this regrettable incident."