China is seeking renewed deliveries of weapons from Russia with a $3.5 billion deal for fighters and submarines in the pipeline.
Despite lingering resentment in Moscow over the copying of its military technology, China's state media reported this week that Moscow had agreed to supply 24 Sukhoi Su-35 fighters and four Amur-class conventional submarines to the People's Liberation Army (PLA).
This would be the first major arms deal between the two nations in almost 10 years, though Russia has not yet confirmed the deal and military experts there said the Chinese announcement was premature because negotiations were continuing.
But the reports signal that Beijing wants to boost its military firepower as it locks horns with Japan over disputed islands in the East China Sea and contends with the US military pivot to Asia.
The need to order some of Russia's most advanced military hardware also indicates that shortcomings remain with some of China's home-grown defence technologies, military analysts said.
"Currently the two sides are working on the relevant contracts and the results are likely to be produced by the end of the year," says Vassily Kashin, an expert on Russia's arms trade with China at Moscow's Centre for Analysis of Strategies and Technologies.
China relied heavily on arms imports from Russia in the early years of its on-going military build-up, but this business began to sour in the mid-1990s when Russia accused Chinese contractors of reverse engineering what was then Russia's front-line fighter, the Su-27.
Aviation industry experts say that China's failure to build high performance jet engines for its fighters is one of the major reasons for its desire to buy the Su-35 in a deal that will be worth at least $1.5bn.
"Engines continue to be the Achilles heel of the Chinese aerospace industry," says Reuben Johnson, a Kiev-based military analyst and correspondent for Jane's Information Group.
The new Russian fighter has more advanced and powerful engines than the Su-27, which give it enhanced performance and manoeuvrability, experts say.
Some analysts suggest Chinese technicians want to adapt the Su-35 engine technology for use in the two stealth fighters now under development for the PLA, but this time around, the Russian defence industry appears more confident that it can protect its intellectual property.
"It is understood that the Chinese will try to steal or copy any system they are given access to," says Kashin. "But, the amount of time they will need to do that might be very significant."
Kashin said one reason for China's earlier success in copying Russian weapons was that hardware, design data and technical experts remained in countries like Ukraine and Belarus after the collapse of the Soviet Union.
China was able to gain access to this knowhow while it reverse engineered the Su-27 and Su-33, a version of the Su-27 built for aircraft carrier operations.
"The new Russian systems cannot be found in the Ukraine or Belarus," says Kashin.
The prospective order for Amur-class submarines, estimated to be worth about $2bn, also suggests that the PLA navy is dissatisfied with the latest versions of its home-grown Song and Yuan class conventional submarines.
Submarines are a top priority for the PLA as it attempts to build a force capable of dominating China's offshore waters and deterring the U.S military from intervening in regional conflicts, analysts say.
Submarines would also be crucial in any territorial clash with Japan, which has a powerful navy and advanced anti-submarine warfare capability.
The PLA navy now has a fleet of more than 60, mostly conventional submarines, according to the International Institute for Strategic Studies and most Western analysts believe the most capable vessels in this fleet are 12 Russian-made Kilo class submarines delivered from the late 1990s.
The Amur class is regarded as a significant improvement on the Kilo class with improved stealth, batteries and weapons.