Continuing shifts in the political and military landscape have pushed Russia and China into a stronger military and industrial alliance. Both countries feel increasingly isolated by the U.S. and its allies. Yet while the expansion of ties between the Russian Armed Forces and China’s People’s Liberation Army comes as no surprise, it has proved slow to materialize.

Russia started negotiations to sell the Chinese a batch of 24 Su-35S single-seat multirole fighters in 2012. Speaking to the media recently, an official with Russian arms export agency Rosoboronexport acknowledged that the talks have seen only limited progress. “The matter is at the stage of the reconciliation procedure,” said Rosoboronexport deputy director general Sergei Ladygin, who headed the company’s delegation to the Euronaval 2014 conference in Paris. “Russia and China continue discussions on the matter of the Su-35S. The process of preparing mutually agreeable documents goes on,” Ladygin stated.

Among other issues, Ladygin attributed the slow pace of the negotiations to recent procedural changes in the sale of equipment to China. “In the past, we signed the contract first and then spent a couple of years awaiting various approvals from the government. Today, we do the reconciliation procedure first, and then sign a contract.”

Similar issues are apparently delaying long-expected contracts for Almaz-Antei S-400 Triumph long-range surface-to-air missiles and Amur-1650 diesel-electric submarines. The “coming” sales of the three aforementioned weapon systems were announced about two years ago.

Meanwhile, Russia continues to supply Mil Mi-17 helicopters to China, with shipments exceeding 300 aircraft. These are supplemented by ongoing deliveries of a relatively small number of Mi-26 superheavy and Kamov Ka-32A11BC firefighting rotorcraft. Other items Russia exports to China include Ilyushin Il-76 airlifters repaired and upgraded from the secondary market, AL31FN Series 3 turbofan engines for China’s J-10 fighter and the D30KP-2 engines that power in-service Il-76 jets and newly assembled B-6 bombers.