Venezuelan President Nicolas Maduro said Thursday that he will re-evaluate relations with Spain in light of this week's incident involving Bolivian head of state Evo Morales' plane, which had to divert to Vienna after several western European countries barred the flight from their airspace.

"What Spain's government did is disgraceful, trying to search the aircraft of a South American president," Maduro said in Caracas on his return from an official trip to Russia and Belarus.

"What does that Prime Minister (Mariano) Rajoy believe, that we South Americans are your slaves?," the Venezuelan leader said.

Morales did not arrive back in Bolivia until shortly before midnight Wednesday, more than 24 hours after he left Moscow, where he attended a conference of gas-exporting nations.

The Bolivian presidential aircraft spent 13 hours on the ground in Vienna as Austrian authorities searched the plane for former U.S. intelligence contractor Edward Snowden, who has released documents exposing Washington's massive surveillance of global telephonic and Internet communications.

The diversion to Vienna came after Portugal, France and Italy barred Morales' plane from their airspace, apparently on suspicion that Snowden was onboard.

Snowden has been stuck in the transit area at Moscow's Sheremetyevo International Airport since June 23 as one country after another rejected his request for asylum.

Washington, which is charging Snowden under the 1917 Espionage Act, revoked his U.S. passport, leaving him unable to board a commercial flight unless some other government provides him with travel documents.

Bolivian officials said Spain initially granted permission for Morales' plane to land for refueling, but later revoked the authorization.

Spanish Foreign Minister Jose Manuel Garcia-Margallo said Wednesday that there was "no prohibition" on the Bolivian plane's entering Spain's airspace.

"We are going to evaluate our relations with the government of Spain, not with the people of Spain," Maduro said Thursday. "The people of Spain have shown solidarity with Evo Morales and solidarity with Snowden." EFE