A cut in Russian gas supplies to Ukraine which could disrupt supplies to Europe remains a possibility, Ukrainian Prime Minister Arseniy Yatsenyuk said on Tuesday, adding he hoped for a deal this week.
"A Russian gas cut remains a possibility. Russia will wage war on Ukraine with all means, including the gas weapon," he told parliament, a day after Moscow pushed back by a week a possible cut in gas shipments to his crisis-hit country.
"We hope to conclude our negotiations with (Russian gas company) Gazprom in the course of this week," he added.
Yatsenyuk said talks were underway in Berlin between Gazprom chief executive Alexei Miller and Andriy Kobolev, the head of Ukrainian gas company Naftogaz.
The prime minister reiterated that Kiev would "never" pay close to $500 (370 euro) per 1,000 cubic metres of gas, the price set by Moscow after the ouster in February of Ukraine's Kremlin-backed president.
"That's not the market price, that's a political price. Such a price does not exist anywhere else in Europe," Yatsenyuk said.
"If Russia thinks of Ukraine as a cash cow, it's wrong," he added.
While Ukraine is hoping for an agreement with Russia by the end of the week, it is prepared to take the case to the Stockholm Arbitration Court if need be.
"If an agreement is not signed, we will take Gazprom to court in Stockholm. The process will last for several months or even years, but we see no other option," he said.
On Monday, Russia gave Ukraine a respite of an extra week, pushing back to June 9 the date when Ukraine must start paying for gas ahead of time or risk a cut in the supply.