GUWAHATI (AFP) - An air force transport helicopter crashed in the mountainous northeast of India on Friday near the border with China, killing all 12 on board, a defence official said. The Mi-17 Russian-made helicopter went down in bad weather shortly after taking off from Tawang in the state of Arunachal Pradesh on its way Guwahati in Assam, defence spokesman R Kalia told AFP by telephone. The helicopter with 12 people on board crashed into a hill with all the dead bodies recovered, Kalia said, adding that 11 of the victims were air force personnel and one was from the army. Most of them were posted on the heavily militarised border between India and the Chinese region of Tibet. We dont know the circumstances leading to the crash and only experts will be able to give us an idea of what went wrong, spokesman Kalia said.