RIO DE JANEIRO, October 30 (RIA Novosti) - A Brazilian military transport plane with 11 passengers on board has disappeared over the hard-to-access jungles of Amazonia, the country's Air Force said on Friday.

According to the Air Force's press release, the Cessna C-98 plane, carrying mostly doctors from Brazil's National Health Fund, took off on Thursday morning from an airfield in the northern state of Acre heading to the neighboring state of Amazonas, and later disappeared from radar screens.

The Air Force immediately launched a rescue operation, involving two H-60 Blackhawk helicopters and a C-105 search-and-rescue plane, but attempts to locate the missing aircraft have been unsuccessful so far.

The doctors from the missing plane were reportedly vaccinating people from indigenous tribes in the region.

The C-98 is a variant of Cessna 208 Caravan, a U.S.-made single turboprop engine, fixed-gear short-haul regional airliner and utility aircraft, which is used by the Brazilian Air Force as a military transport plane.