Russia and China have kicked off their first large-scale joint war games, involving 10,000 troops, in the port city of Vladivostok in Russia's Far East. Officials say the exercises, dubbed Peace Mission 2005, are aimed at countering new threats and challenges, such as terrorism and separatism.

The week-long drills, simulating intervention in a country wracked by ethnic violence, began with political and military consultations between Russian and Chinese military delegations.

In comments broadcast on Russian television from Vladivostok, the chief-of-staff of Russia's armed forces, General Yuri Baluyevsky, said the primary aim of the land, air and sea drills is peaceful.

Mr. Baluyevsky echoed his Chinese counterpart in saying the two sides are not striving to build a strategic military alliance, in order to confront or threaten a rival third party, as some may fear or suggest. He says the drills seek to fine-tune command and control preparations in the event of a large-scale terrorist attack or emergency.

A Russian professor of military sciences, German Petrenko, also discounts the threat level of the games. In an interview with Russia's Echo Moscow radio, Mr. Petrenko says the maneuvers mainly aim to protect Russia's national interests.

Mr. Petrenko, a military reservist, says the nod east, to China, reflects what he calls the current strategic and geographical reality after the break-up of the Soviet-led Warsaw Pact military alliance.

Others say the joint exercises are an opportunity for Moscow to demonstrate its weaponry to China, one of the biggest consumers of Russian military hardware.

The exercises also highlight growing ties between Moscow and Beijing. Their relations have warmed following decades of Cold War-era rivalry, reflecting their mutual concerns over perceived U.S. dominance in global affairs, as well as shared interest in combating extremism and separatism in Central Asia.

Despite the attempts to downplay controversy, western news reports note the unusual involvement of warplanes that can carry conventional or nuclear-tipped missiles during the drill. Such planes are not normally seen during peacekeeping exercises.

The United States was informed of the maneuvers in advance, but reportedly chose not to send observers. State Department Spokesman Sean McCormack earlier said that the United States expects that, whatever activities take place during the drills, they will only be ones that further regional stability and peace in Asia and the Pacific.