Moscow's year-long bombing campaign in Syria has showcased the "reliability" of Russian weaponry, as the Kremlin has helped stabilise the war-ravaged country, Defence Minister Sergei Shoigu said Thursday.

"In that period we have managed to stabilise the situation in the country (and) liberate a significant part of the territory from armed international terrorist groups," Shoigu told a conference.

"Many types of modern weapons produced in our country were tested in difficult desert conditions and generally have shown their reliability and effectiveness."

The comments come as international anger grows over Moscow's air support for a ferocious regime assault on eastern Aleppo that has prompted accusations of potential war crimes.

The United States on Monday suspended talks with Russia on a ceasefire in Syria in protest at Moscow stepping up its bombing campaign.

Russia launched its military operation in Syria last September to back up long-time ally Bashar al-Assad to Western ire, helping to shore up the regime's embattled forces.

Russia's military has denied repeated accusations that it has struck civilian targets in the country during its year-long bombing campaign.

Moscow has used Syria as a testing-ground for a range of new weaponry including long-range missiles fired from ships, submarines and warplanes.

Those include the X-101 rocket that has a range of 4,500 kilometres (2,800 miles) and was fired from bombers that took off from bases in Russia, Shoigu said.

Built on the foundations of its Soviet-era predecessor, Russia's arms industry is a key source of income for the country and brought in some $14.5 billion (13 billion euros) in 2015.