BEIJING - China's military launched war games Tuesday aimed at deploying forces at long distances, reflecting moves to ensure security in the restive western regions of Tibet and Xinjiang.

The exercises will send 50,000 armoured troops - the People's Liberation Army's "largest-ever tactical military exercise" - to unfamiliar areas far from their bases for two months of live-fire drills, state media reported.

The exercises involve four brigades from the major military regions of Shenyang, Lanzhou, Jinan and Guangzhou, which all will be deployed at least 750 miles (1,200 kilometres) from their bases, the reports said.

Such deployments would be needed to reinforce units in Tibet and Xinjiang, where security forces have battled renewed ethnic conflict and anti-government violence over the past two years.

China also continues to claim territory along its remote border with India over which the two fought a short but bloody border war more than 45 years ago. Its navy, meanwhile, has grown increasingly assertive in defending territorial claims in the South China Sea.

"In the unprecedented exercise, one of the PLA's major objectives will be to improve its capacity of long-range projection," the official Xinhua News Agency said. It said the war games constituted the army's "largest-ever tactical military exercise," although numbers of troops involved were relatively small.

The 2.3 million-member PLA is the world's largest standing military.

Long-distance deployment is also aimed at dealing with natural disasters such as last year's devastating Sichuan earthquake, which left almost 90,000 people dead or missing, according to Ni Lexiong, a military expert at Shanghai University of Political Science and Law.

"This is really about a rapid response to sudden events in Tibet and Xinjiang, but also the military will play an increasing role in moving supplies and responding to disasters," Ni said.

The PLA has undergone a rapid upgrade in recent years in both equipment and doctrine.

Two decades of almost annual double-digit increases in military spending have allowed the addition of cutting-edge fighter jets, nuclear submarines and hundreds of ballistic missiles pointed at rival Taiwan. China has announced a 14.9 per cent rise in military spending in its 2009 budget, to 480.6 billion yuan ($70.3 billion).

At the same time, training and tactics have been redesigned to take advantage of information technology and China's much-improved economy and infrastructure.

The military has also taken steps to emerge from its traditional veil of secrecy and engage with other nations, most strikingly in sending ships to join the international anti-piracy flotilla off the coast of Somalia this year.