Turkey's concessions will hit Gazprom's revenue; this year, the company's export earnings will be halved to $40 billion.
Turkey has received the right to postpone payments for russian gas worth $4 billion until 2024.
The agreement was signed between Gazprom and the state-owned energy company Botas. The latter, according to the sources, has already exercised the right to defer and postponed payments of $600 million to the next year.
Putin was personally asked for gas concessions by Turkish President Recep Erdogan during a meeting in Sochi last August.
He insisted on a discount on gas, which had become too expensive for the fragile Turkish economy: inflation in the country exceeded 80% last year.
As a "return favor," putin offered Erdogan to create a gas hub in Turkey that would replace the Nord Stream pipeline system destroyed by the bombings for supplies to Europe.
In March, Turkish Presidential Spokesperson Cagri Erhan said that negotiations on the hub had been suspended. "Now we do not have the money to build it. If russia has the money, please start building the hub. It all depends on investment," he explained.
Turkey's concessions will hit Gazprom's revenue, which has already lost its key European market, with supplies to which have fallen to a 30-year low. This year, the company's export revenues will be halved to $40 billion, according to BCS analyst Ronald Smith.