Nearly 10,000 Chinese and Russian troops are carrying out joint military exercises for a second week off eastern China's Shandong peninsula. The exercises are highlighting growing ties between the historic rivals.
Chinese officials eagerly showcased the exercises, with government newspapers heralding them as the start of a new strategic alliance between the two giant neighbors.
Some experts - both Chinese and Western - saw the maneuvers as a message to the United States that Washington's influence in the East and Central Asia is not without rival.
June Dreyer is a political science professor at the University of Miami and a member of the U.S.-China Economic and Security Review Commission, which met with Chinese officials in Beijing this week. She views the exercises as a sign of growing unease in Beijing as the United States strengthens its ties with others in the region.
"I think they were designed to send a signal to the United States that the United States had better be careful. And, I think that to some extent, Japan was another target. I think the Chinese have been very concerned with a Japan-United States alliance," said June Dreyer.
Russia and China did not invite the United States to observe the maneuvers, which have included a simulated naval blockade, the firing of air-to-air missiles, and other exercises involving hardware including nuclear submarines, destroyers and helicopters.
Some of the drills are taking place not far from Taiwan. Analysts say Beijing wants to display its military might to the rival government of the island, which China claims as part of its territory and has threatened to take by force.
For Russia, the benefits of the joint maneuvers are largely economic. The exercise provided Moscow an opportunity to showcase the latest of the hardware it wants to sell to China. Beijing, which is rapidly expanding its military capabilities, is already the biggest buyer of Russian military equipment.
Yu Bin, a senior research associate for the Shanghai Institute of American Studies, says Russian leaders do not appear to want any part in the Taiwan dispute.
"They do not want to get too much involved in the Taiwan Strait. Though some low-level tensions may help them sell weapons to China. So the Russians have their own agenda, not completely overlapping with the Chinese," said Yu Bin.
The exercises, while meant to show that an alliance is maturing between the two countries, do not change the centuries of conflict and suspicion that characterize their historical relationship.
Chinese and Soviet forces clashed along their border in 1969, and territorial disputes linger. Moreover, China's recent emergence as a major investor in Russia's Far East has caused unease among many Russians.
"Many Russian businessmen and politicians [who] still perceive China as a hypothetical threat now think [if] 'China invests in our assets, it could be dangerous for Russian security,'" said Vasily Mikheyev is a Sino-Russian relations specialist at the Russian Academy of Sciences in Moscow.
Some analysts say that a deep and lasting alliance does not appear likely at this stage, noting that Beijing and Moscow have - despite warming ties - failed to reach definite agreements on key issues such as the construction of an oil pipeline and long-running Chinese claims over Russian territory.
Professor Yu Bin at the Shanghai Institute of American Studies says economic interests of both sides and their growing trade ties to the United States may be what ultimately determine the future of Sino-Russian relations.
"For both Moscow and Beijing, their fundamental interest is to have a normal working relationship with the United States. The problem is that if you look at the triangular [equation] both Russia and China actually need more from the American side than perhaps from each other," said professor Yu Bin.
The United States has been monitoring the exercises off the Shandong Peninsula, but Washington has expressed little concern over their long-term significance.
In remarks this week, U.S. Defense Secretary Donald Rumsfeld said he did not find the joint exercises notable and said that while U.S. forces are observing what is taking place, he did not see anything in the drills that was threatening to "Taiwan or anyone else."