Speaking during a meeting with Turkish President Tayyip Erdogan on the sidelines of a Shanghai Cooperation Organisation summit in Uzbekistan, Putin said: "Our agreement on deliveries of Russian natural gas to Turkey should come into effect in the near future, with 25% of payment for these deliveries in Russian roubles."

Since Western countries imposed sweeping sanctions over its Feb. 24 invasion of Ukraine, Russia has sought to conduct as many transactions as possible in currencies other than dollars or euros - the usual default currencies for energy contracts, in particular.

It has also demanded that payments for some gas exports be made in roubles, in some cases in contravention of existing contract terms.

Several European Union member states including Poland and Bulgaria have had gas supplies from Russia cut off after refusing to make the rouble payments.

Turkey has maintained warmer relations with Russia than European Union countries have.