Rescuers have confirmed on Saturday that all the 18 people on board a plane have been killed in Thursday's air crash in Bahorok forest of North Sumatra.

"All the people on board have been dead," Head of the Search and Rescue Office in North Sumatra Hadi Tugiman told Xinhua by phone from North Sumatra.

The CASA 212 aircraft operated by PT Nusantara Buana Airline lost contact on Thursday and was found hours later in the Bahorok forest.

The plane was carrying a pilot, co-pilot, two technicians and fourteen passengers from Medan, the capital of North Sumatra, to Kutacane of Aceh province, said Bambang Ervan, spokesman of Indonesia's Transport Ministry.

Air Marshal Sunarbowo Sandy, head of the rescue operation, told Xinhua that 15 of officers of army and air force have been working at the site. They will make a helipad so that the helicopters could land to evacuate the dead bodies," he said.

Four helicopters have been deployed to help over 100 rescuers from military and Search and Rescue Office in North Sumatra with the evacuation, said Sunarbowo.

"The bodies are going to be brought to Adam Malik General Hospital in Medan," he said.

Poor geographical conditions and bad weathers have hampered the evacuation so that the authorities decided to pull back all tens of military officers and rescuers, trying to reach the scene through land.

Having known that none of the people on board survive, some family members waiting at the post in Medan complained about the rescue operation, according to a local television.

"They could have been alive should the rescuers do it faster," said a family member of the victims.

Lack of safety standards has been blamed for air crashes in Indonesia.