"Based on observations and the search we carried out with the air force commander, we have reached the conclusion that the impact was such that it should have resulted in the instantaneous death of all of those who were aboard the aircraft," Chilean Defense Minister Andres Allamand told reporters Saturday. A major search operation had been launched late Friday in the waters around Robinson Crusoe island in the Juan Fernandez islands, some 700 kilometers (435 miles) west of the South American coastline, and some debris from the missing plane has been located in the sea. So far, only four bodies have been recovered. "We have found two female bodies and two male bodies," said air force chief Maximiliano Larraechea. As Chile's navy and air force headed the search, fishermen in their boats left the archipelago early Saturday in the hope of turning up survivors. Allamand said the plane, a turboprop-powered Casa 212, made two attempts to land on the main island but failed, "after which contact was lost." Strong winds were being blamed for causing the light aircraft to be blown off course, but it was unclear what had definitively caused the crash. The air force earlier said that as the aircraft was "getting closer to the island, radio communication with the plane was lost," prompting the launch of the search effort. Government spokesman Andres Chadwick said the 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. Among those whose bodies were not yet found were popular Chilean television host Felipe Camiroaga, who was part of a TVN crew heading to the archipelago to report on reconstruction efforts following a huge February 2010 earthquake and tsunami. President Sebastian Pinera said that while he was not losing hope, he was not optimistic. "This was a very serious accident, and the forecast is not favorable," the Chilean leader declared in a statement. Tributes for the victims 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. The reburial of former president Salvador Allende, planned for Sunday, was meanwhile postponed due to the crash, with the late leader's foundation saying it would be held at a later date. Allende's remains had been exhumed and examined in a bid to unravel mysteries surrounding his demise amid the 1973 coup. Experts concluded he had committed suicide, and was not murdered as some had alleged. The island, near which the accident occurred, was made famous by 18th century British author Daniel Defoe, who used it as the location for his popular novel "Robinson Crusoe."