Chinese search teams, traveling on foot, are carrying the remains of the crashed military helicopter and the bodies of those aboard to earthquake relief headquarters in the town of Yingxiu, military sources said Wednesday.

The remains of the crashed military helicopter are seen in this picture taken on June 11, 2008. The Mi-171 military transport helicopter crashed at 2:56 pm on May 31 while transferring 13 injured civilians from the epicenter of the May 12 quake in the southwestern Sichuan Province. [Xinhua]

As of 3 p.m. Wednesday, more than 1,000 militia, reservists and soldiers had been mobilized for the recovery operation, as the site was too mountainous and the forest cover too thick to allow rescue helicopters to land.

Some of the debris of the crashed aircraft reached the quake-ravaged Yingxiu around 11 a.m. Wednesday, where military experts confirmed it belonged to the military helicopter, the military sources said.

However, the black box voice recorder hasn't been located and the search was still on.

A 40-strong team had reached the crash site at 11:30 a.m. and were expected to carry the dead bodies to Yingxiu about 11 a.m. on Thursday.

So far, the remains of all 18 persons aboard the helicopter, including five crew members and 13 civilians injured in the May 12 earthquake, have all been found at the crash site.

The Mi-171 military transport helicopter crashed at 2:56 p.m. on May 31 while transferring 13 injured civilians from the epicenter of the May 12 quake in the southwestern Sichuan Province.

One person formerly reported as having been on board did not take the helicopter.

More than 100 helicopters were sent to locate the aircraft, while more than 300 rescue teams, consisting of more than 10,000 troops, armed police, militia, reservists and local residents, combed the region to search for the missing aircraft.

The debris of the Mi-171 helicopter was found in the bushes northwest of Yingxiu Township at 10:55 a.m. on Tuesday.

"The Mi-171 military transport helicopter was imported from Russia in 1993," Ma Gaihe, an officer with the General Armament Department of the People's Liberation Army, told a press conference in Beijing Wednesday afternoon.

"The chopper was equipped with an automatic navigation system and should be able to carry out missions in difficult weather," Ma said.

The remains of the crashed military helicopter are seen in this picture taken on June 11, 2008. The Mi-171 military transport helicopter crashed at 2:56 p.m. on May 31 while transferring 13 injured civilians from the epicenter of the May 12 quake in the southwestern Sichuan Province. [Xinhua]

Ma added that the crash was caused by the helicopter's sudden encounter with strong turbulence and the treacherous terrain near the crash site.

According to Ma, the military used satellites, radar, thermal infrared remote sensing and electronic positioning technologies to locate the crashed chopper during the 11-day search.

"However, many metal structures, such as power poles, collapsed after the May 12 quake," Ma said. "These steel structures look very similar to the debris of the crashed chopper when viewed by our search technologies, and we have to check each possible site on foot because of the deep valleys and dense forests limiting access of rescue helicopters.

"We will learn from our quake relief experience and improve the military's ability to perform in non-combat situations," Ma said.

Editor: Yan