(CNN) -- A Bolivian Air Force plane missing since Thursday crashed in a remote, mountainous area, killing two pilots and four United Nations workers, a U.N. official said Saturday.
A day earlier, a local mayor claimed to have found the plane and its passengers safe and sound, but the Air Force on Saturday found the wreckage, confirming that that was not the case.
"The plane was completely destroyed and burned," Robert Brockmann, spokesman for the U.N. field office in Bolivia, told CNN.
The plane was found northeast of La Paz, the capital, in an overgrown area with steep cliffs, Brockmann said. The closest village to the site of the wreckage is La Merced, though it was not easily accessible, he said.
The cause of the crash has not been determined.
The four U.N. workers belonged to the United Nations Office on Drugs and Crime. They were identified as Ivan Alfaro, Patricia Delgado, Cinthia Moreno and Stephan Campos.
At the time of its disappearance, the plane was carrying out an overflight of coca-producing areas in the Los Yungas region of the country, north of La Paz. It was the last week of what had been months of such overflights.
The plane had left El Alto International Airport in La Paz at 10:30 a.m. Thursday and was expected back at 2:30 p.m. The Air Force initiated a search after the plane never returned.