Russia is using cryptocurrencies in its oil trade with China and India to skirt Western sanctions, according to four sources with direct knowledge of the matter.

While Russia has publicly encouraged the use of crypto and last summer passed a law to allow digital currency payments in international trade, its use in the country’s oil trade has not previously been reported.

Some Russian oil companies are using bitcoin, ether and stablecoins such as Tether to smooth the conversion of Chinese yuan and Indian rupees to Russian roubles, the sources said, adding that it is a small but growing part of Russia’s overall oil trade, which according to the International Energy Agency was worth $192 billion last year.