Beijing has agreed to clear a Soviet-era debt totaling 1.57 million Swiss francs ($1.72 million) in a move likely to restart a much bigger debt retirement plan that will involve the delivery of Russian-made helicopters, Russian Deputy Prime Minister Dmitry Rogozin said on Friday.

Moscow and China had previously agreed to retire $408 million in Soviet debt with deliveries of Russian goods and services, including 20 Kamov helicopters worth about $355 million, Ria Novosti News Agency reported.

However, the project stalled after China failed to write off a smaller debt of just $1.72 million, according to Ria Novosti.

Rogozin said on his Twitter account that the smaller debt had been paid using Russian goods and services in 2008. It's not clear why the larger debt-repayment plan appears only now to be back on track.  

With the settlement of the "long-term problem" of the $1.72 million debt, the Russian Finance Ministry is now able to finance the contracts signed between the helicopter suppliers and Chinese clients. The first deal would involve the export of the 20 helicopters.

The new agreement shows practical and beneficial progress in the economic and strategic cooperation between the two countries by solving a long overdue debt issue, said Xing Guangcheng, a Russia studies expert and director of the Research Center for Chinese Borderland History and Geography.

The Kamov Ka-27/28 helicopters have become an important asset for Chinese navy destroyers and frigates and are used for anti-submarine warfare and other missions. The 10-ton class Ka-27 series helicopters are suitable for vessel-based aviation. Though the Chinese made four-ton-class Z-9 helicopter can also perform similar missions, the Ka-27 can carry a heavier payload.

Apart from the Kamov deal, Russia and China are also cooperating on the design of new types of heavy helicopters. According to a previous Global Times report, experts in the two countries are discussing the layout, weight class and market potential of the new heavy helicopters.

Apart from military uses, heavy helicopters play an important role in various fields including emergency rescue and transportation of strategic supplies, Xing told the global Times.

Russia leased a 50-ton-class Mi-26 heavy transportation helicopter to China in 2008, which significantly contributed to the disaster relief work in the aftermath of the Wenchuan earthquake.