URUMQI, July 29 (Xinhua) -- A Chinese army aviation unit, consisting of 16 helicopters, flew to Russia on Sunday for a joint anti-terrorism drill to be held by the Shanghai Cooperation Organization (SCO).

    The helicopters took off from an airport in northwest China's Xinjiang Uygur Autonomous Region at 9:54 a.m. and would fly 2,700 kilometers to get to the drill venue, said Major General Ma Xiangsheng, one of the top Chinese officers in charge of the drill.

    "The flight will be a good test for China's army aviation troops due to its long distance, complicated topographic and climatic conditions on the way as well as possible language barriers with the ground service in Russia," Ma said.

    "The formation will fly over Altay Mountains with an altitude over 4,000 meters when it crosses the Sino-Russian border, which demands full technical preparations," Ma said.

    "The unit has carefully studied the map, made several counterplans and loaded the helicopters with sufficient aviation materials to ensure a successful flight," he said.

    According to him, China will send to Russia a total of 16 Mi-17transportation helicopters and 16 Z-9 armed helicopters, which are mixed into two units to fly to Russia, Ma said.

    The "Peace Mission 2007" drill will be carried out in Chelyabinsk in Russia and in Urumqi, capital of Xinjiang.

    The six member countries of the SCO -- China, Kazakhstan, Kyrgyzstan, Russia, Tajikistan and Uzbekistan -- will stage the joint anti-terrorism drill from Aug. 9 to 17.

    It will involve 6,000 military personnel, including 4,700 Russian soldiers and 36 aircraft.

    Ahead of the army aviation unit's departure, an advance troop of China's People's Liberation Army (PLA) flew to Russia on Friday.

    The advance troop comprises seven units, including command and logistics corps, and its main task is to make preparations for the main force arrival at the drill region.

    Also on Friday, the first group of China's main force for the drill arrived at Manzhouli, a border city in north China's Inner Mongolia Autonomous Region, and transferred to a Russian military train and entered Russian soil, the first time the PLA has entered Russia for a military exercise.

    The main force of China's 1,600 troops set off by train on July19 from Xinjiang, along with armaments needed for the drill, and they passed through Xinjiang, Gansu, Ningxia and Inner Mongolia, already covering a distance of more than 5,300 kilometers.

    It will take about another week for the main force to arrive at the drill region. Fuel, water, food and security will be provided by the Russian military.

    The Chinese forces come from the army and air force, including airborne and logistic units, according to the Ministry of Defense.

    The Chinese soldiers will travel a total distance of 10,300 kilometers.

    "This is the first time the PLA has sent so many soldiers and armaments so far," said Qiu Yanhan, deputy commander of the Chinese contingent.

    The exercise would help strengthen relations between the militaries of SCO members and enhance cooperation in defense security, said Guo Boxiong, vice chairman of China's Central Military Commission.