Some 1,000 search and rescue personnel in Malaysia combed thick jungle Monday for a missing air force helicopter with six officers on board, a military spokesman said.

Rain and fog had hampered the intensifying search of dense, hilly tropical rainforest for the aircraft, which disappeared Friday, Major Zulkiflee Abdul Latiff, a spokesman for the Royal Malaysian Air Force, told AFP.

"So far there are no new developments. It really depends on the weather and the skill of the search and rescue team," he said.

Air traffic control lost contact with the Nuri helicopter, a Sikorsky S-6T, shortly after it took off on a routine flight from the capital, Kuala Lumpur, to central Pahang state.

The search for the helicopter and its crew is the biggest mounted in Malaysia in recent years, involving a number of agencies and more than 15 helicopters and planes, the state Bernama news agency reported Monday.

A US navy Sea Hawk helicopter has been scrambled to help the search, while on land indigenous villagers familiar with the terrain are also helping.

Zulkiflee said the US military helicopter joined the search but thick fog was hampering the mission.

Steep hills and dense forest were also hampering efforts to find the helicopter and recover the crew.

The aging Nuri helicopter, the work horse of the air force, entered service 39 years ago.

It does not have an emergency locator transmitter which would allow rescuers to locate it.