The US has imposed sanctions on the Chinese military over its purchasing of Russian military jets and surface-to-air missiles.
It says such purchases contravene US sanctions on Moscow introduced over Russian actions in Ukraine and alleged interference in US politics.
China recently bought 10 Russian Sukhoi Su-35 fighter jets and S-400 missiles.
Beijing has not joined in the sanctions imposed on Moscow by the US and its Western allies since 2014.
Relations between the US and Russia deteriorated rapidly after Moscow annexed Crimea from Ukraine in 2014.
Russia's alleged meddling in the 2016 American presidential election and military involvement in Syria's ongoing civil war increased tensions.