Observers say an armed raid on the headquarters of Ukraine’s state-owned gas company Naftogaz represents a fresh twist in the power struggle between the country’s president and prime minister.Masked security service officers searched the Kiev offices as part of an inquiry into the gas price dispute between Russia and Ukraine in January. The service is controlled by President Viktor Yushchenko, the former ally-turned-rival of Prime Minister Yulia Tymoshenko, who led the negotiations on the contracts. “Whether or not Ukraine pays its gas bill for the month of February in the next two days, as agreed in the contract, depends on several things. One of them is the payment by officials in Kiev, another is payment by residents. It also depends on the outcome of the current situation,” Yushchenko said after a cabinet meeting. But Tymoshenko, on an official trip to Paris, said someone was trying to sabotage her work on the contracts. “Ukraine has already signed agreements with Russia, with a very precise structure, so things work according to this formula and there are not going to be any more rows of this nature, and Ukraine will always be a reliable partner in terms of the transport of gas to Europe,” she said. This latest row could once again threaten domestic supplies of gas from Russia and possibly reignite the threat of another midwinter shutdown like the recent one that left 18 Western countries literally out in the cold in January.