“The money is on our transit account,” the source said.
Earlier, a Naftogaz press service spokesman said that the company had sent the $30 million to Gazprom on Wednesday.
In the summer 2014, Gazprom switched Ukraine to a prepayment system for gas deliveries over Kiev's gas debt that at the time surpassed $5 billion.
In October 2014, Moscow and Kiev signed the "winter package" agreement, providing Ukraine with gas supplies until the end of March with a $100-discount per 1,000 cubic meters. Moscow later extended the deal for the second quarter of 2015, taking into account Kiev's economic difficulties.