BANGKOK (AFP) - Five soldiers were killed when their helicopter crashed in bad weather during a mission to airlift troops from a remote jungle area in central Thailand, a senior military official said Sunday. Heavy rain and poor visibility hampered rescue efforts, said Lt Gen Udomdej, the commander whose remit includes the National Park, where the accident happened on Saturday. Troops at the park confirmed all five passengers were killed, Udomdej said. The helicopter had been sent to collect about 35 soldiers who had been on patrol in the park as part of measures to combat deforestation, but crashed.