A US defense official says a US Navy plane may have crossed accidentally over Venezuela's airspace Saturday night. The incident triggered protests from President Hugo Chavez's government. An official familiar with the report said Monday that the S-3 Viking aircraft, based in Curacao, was on a training mission in international airspace near Los Roques Island, Venezuela, and experienced "intermittent navigational problems." The official spoke on condition of anonymity because of the sensitivity of the issue. The aircraft is used for counter-narcotics missions. Navy crew on the S-3 reported they had a brief radio conversation with air traffic control personnel in Maiquetia, and concluded they had flown mistakenly into Venezuelan airspace, the official said.