* The army says the drill, codenamed Stride-2009, is not aimed at specific threats. It will continue for two months.

* Civilian passenger and cargo aircraft will be used in addition to air force planes.

China's army is on the move - not merely in terms of the changes it is going through as its adapts to meet modern challenges, but quite literally too.

Yesterday, 50,000 troops were moving at the start of the army's largest-ever tactical event, in which they will be mobilized and transported vast distances across the nation.

With air force cover, an infantry section from Northwest China set out on the first day of the exercise on a journey that will take it across five provinces in 13 days before the troops reach Northeast China.

While China has held an annual military drill for several years, the latest one is focused on the trend within the People's Liberation Army (PLA) for improved mobility over long distances by using both military and civilian resources, experts told China Daily.

Military experts say it offers instead a rare opportunity to test the PLA's emergency response capability, which could be crucial in countering new security threats, particularly those from terrorists, extremists and separatists.

"I think, this time, we will see some real action that displays the army's modernization. Finally, we will see army mobilization on a large scale, similar to what is often seen in Hollywood war movies," Li Xiao, a military fan nicknamed 'Land Tiger' on the online fan club Super Camp, said yesterday.

The drill will be the largest tactical exercise for the PLA since it was established 82 years ago.

The PLA General Staff Headquarters is in charge of the mission.

Army divisions from each of four military commands, which include Shenyang, Lanzhou, Jinan and Guangzhou military areas, will exchange positions during a series of live-fire drills in the exercises.

They will use civilian rail and air transportation in addition to military resources for the first time during a PLA military drill.

Infantry divisions from Shenyang Military Command in Northeast China will be transported to Lanzhou Military Command in Northwest China.

Another pair of infantry divisions, from Jinan Military Command in East China and Guangzhou Military Command in the south, will be switched.

Civilian passenger and cargo aircraft will be used in addition to air force planes.

Heavy weaponry, including tanks and infantry vehicles, will be carried by rail. Lightly armed troops, deployed to Jinan Military Command, will be deployed by China Railway High-speed trains traveling at speeds of up to 350 km per hour.

"I'm sure the soldiers will enjoy the speedy ride," said Li Daguang, an armament specialist with the University of National Defense.

"Civil resources will allow the army much more mobility to cope with the many new security threats, both on the homeland and overseas," Li said.

The expert said the last time civilian equipment, such as cargo planes, were widely used to mobilize armed forces came during last year's massive earthquake relief work in Sichuan.

"The army must trust the civil resources and apply them more for greater mobility. To build and maintain heavy transportation equipment for the army would be wasteful," Li added.

The PLA has held cross-division military drills in recent years, but on a much smaller scale.

The cross-division military drill will also serve as a test for the army, which is seeking to break away from the old-fashioned command mechanism, analysts said yesterday.

Armed forces under the control of four unfamiliar military commands will switch positions during the lengthy drill, which is aimed, in part, at "breaking free from the restrictions caused by having military areas, armed forces divisions and other institutional gaps", reported the official Xinhua News Agency, quoting army sources.

For several years, there has been speculation that the PLA was mulling the idea of establishing a cross-sectional mechanism to replace the traditional decision-making procedure.