Nearly 9,000 Russian and Chinese troops began a mock assault on the beaches of northern China Tuesday in the final stage of unprecedented joint war games between the two former Cold War (search) rivals.

The live-fire exercise, dubbed "Peace Mission 2005," involves about 7,000 Chinese troops and 1,800 Russians, along with warships, warplanes and amphibious tanks.

Operations began with a simulated naval blockade off the coast of the Shandong Peninsula in the Yellow Sea, southeast of Beijing (search), China's official Xinhua News Agency reported. Chinese state television showed ships and warplanes firing missiles and rockets while military music blared from shipboard speakers.

Chinese participants included three destroyers, three frigates and one submarine, along with naval aircraft, Xinhua said. They were joined by an anti-submarine vessel, missile destroyer, helicopters and a surveillance plane from the Russian navy, it said.

Top Chinese and Russian generals have sought to reassure the region that the exercises aren't directed against any third nation. Under the fictional scenario for the exercises, the forces have a U.N. mandate to stabilize a country plunged into violence by ethnic strife.

Yet Chinese media have also said the exercises are intended to advertise China's determination to deal with regional terrorist, extremist and separatist threats — the last a likely reference to self-governing Taiwan (search), which China has vowed to reclaim by force if necessary.

The games "will frighten the three evil forces of 'ethnic separatism, religious extremism and international terrorism,'" Maj. Gen. Peng Guanglian, a frequent hardline critic of Taiwan and the United States, was quoted as saying in an interview with the Shanghai's Oriental Morning Post.

The eight-day exercises were inaugurated last week in the Russian port of Vladivostok; they end Thursday.

The war games reflect strengthening ties between Russia and China over shared concerns about U.S. dominance of world affairs. U.S. officials have said they are watching the exercises closely and hope they will help support regional stability.

Russia is also seeking to sell more arms to China, one of its leading customers, including long-range strategic bombers able to carry nuclear weapons.

The exercises have sparked controversy in Russia over how closely the nation should cooperate with China, which many Russians see as a potential threat because of its size, economic might and proximity to sparsely populated, resource-rich Siberia.

The exercises are the first major drills solely involving Russian and Chinese forces, although they have previously joined in border security exercises with other members of the Shanghai Cooperation Organization, a group of six Central Asian nations dominated by China and Russia.

Defense ministers and other observers from SCO states were on hand to witness the exercises, according to the official People's Liberation Army Daily.

Russia's Defense Minister Sergei Ivanov (search) was headed to China to watch soldiers stage an amphibious landing and simulate a battle to capture a coastal area on Wednesday and Thursday, the ITAR-Tass news agency reported from Moscow.

Russia was China's chief ally after the founding of the communist state in 1949, but the sides fell out in the 1950s over ideology and fought a series of border skirmishes.

Ties have strengthened following the rise of Russian leader Vladimir Putin (search), aided by China's hunger for Russian oil and gas and mutual concerns over U.S. military deployments on the countries' borders in Central Asia.