Chile on Sunday declared two days of national mourning as officials said some bodies from the 21 people on board an air force plane that crashed off Robinson Crusoe island in the Pacific may never be found. The tragedy has prompted nationwide grief, and the discovery of more human remains beyond the four bodies recovered earlier added to the trauma that has enveloped Chile since the CASA 212 turbo-prop plane went down late Friday during a failed attempt to land. The search continued on Sunday but the government said there was no hope of finding survivors as all on board the plane, believed to have been thrown off course by strong winds, would have died on impact. President Sebastian Pinera said mourning on Monday and Tuesday would allow people to express solidarity with the families of victims, who included one of the country's best-known television personalities. Defence Minister Andres Allamand, who is on the island, said the condition of more remains recovered on Sunday had indicated that some victims may never be reclaimed. "We must prepare for the possibility that we will not find some of the bodies," said Allamand. On Saturday he told reporters that the air force plane had made two abortive attempts to land before radio contact was lost. Thousands gathered at state broadcaster TVN to remember daily morning talk show host Felipe Camiroaga, who was traveling to the island with a crew to report on reconstruction efforts after a massive earthquake and tsunami caused devastation last year. "I cannot imagine the morning without Felipe," said one devastated female fan in tears outside the television station, whose headquarters has been deluged in flowers, stuffed animal toys, candles, and messages of condolence. Robinson Crusoe, the island which is believed to have been the setting for the famous novel by 18th century British author Daniel Defoe, is the main island of the Juan Fernandez archipelago, which lies in the Pacific some 700 kilometers (435 miles) west of the South American coastline. Prior to the recovery of the latest remains, air force chief of staff General Maximiliano Larraechea said Sunday the search would continue "until we find each one" of the 17 missing. The Chilean navy is using sonar equipment to try to locate the fuselage of the aircraft, where the remaining crash victims are likely to be found. "Yesterday, the bodies of some victims surfaced fairly rapidly, which leads us to believe that the rest are with the fuselage," Larraechea said. Although winds are being blamed for the crash, the accident's official cause remains unknown. Government spokesman Andres Chadwick said the four bodies identified were those of Erwin Nunez, an air force corporal; Galia Diaz, with the National Cultural Council; Roberto Bruce, a TVN network journalist; and Silvia Slager, a TVN producer. Tributes for the victims have poured in from across South America. Foreign ministers from member nations of the Organization of American States, gathered for a meeting in the Chilean port city of Valparaiso, held a moment of silence. Pope Benedict XVI said he was "deeply saddened" to learn of the accident, in a message relayed by the archbishop of Santiago, Ricardo Ezzati.