An armed police raid on the headquarters of Ukraine’s state energy company, Naftogaz, is causing new concerns about Europe’s gas supply from Russia. Scuffles broke out as officers entered the building in Kiev in search of original copies of a new gas contract between Russia and Ukraine.Without these documents it is feared Ukraine will not be able to make its latest gas payment, raising the prospect of another cut in supplies to the West. One Naftogaz official claimed the agents had not identified themselves and that it was only through news reports that he knew they were police. Analysts believe the operation is linked to a dispute between Prime Minister Yulia Tymoshenko and President Viktor Yushschenko, former allies who are now bitter political enemies. In January Tymoshenko clinched a supply deal with Russia in which she accepted a considerable rise in prices for Ukraine. It brought an end to a dispute which had halted the gas flow from Russia, but the contract was criticised as a “defeat’ by Yuschchenko. He has said the raid was legally justified. Naftogaz has acknowledged the seizure of documents would make it difficult to make its next payment to Russia, due this weekend, but that it was doing everything it could to ensure it went ahead.