The Ukrainian Prosecutor General's Office is investigating a separate criminal case relating to the signing of a gas contract with Russia in January 2009, office spokesman Yuriy Boychenko said on Monday.
The first case on the 10-year contract with Russian energy giant Gazprom on the supply of Russian gas to Ukraine at international prices, involving former Ukrainian Prime Minister Yulia Tymoshenko, is already in court.
The Ukrainian Prosecutor General's Office initiated the case against Tymoshenko in April, charging her with abuse of office for signing the contract that prosecutors said cost Ukraine $440 million in lost revenues. As a close ally of Russia, Ukraine had previously received a discount on Russian gas.
The second case "has been detached into a separate legal process on the signing of gas contracts," Boychenko said, adding that details will soon be made public.
Oleksandr Turchynov, who was Ukrainian first deputy prime minister in the Tymoshenko government, said he and former Deputy Prime Minister Hryhoriy Nemyrya were questioned on Monday on the second case.
He said the case was politically motivated.
"All these investigative activities are solely politically motivated. There is no legal position or economic substantiation in these cases," he said.