Budapest - Hungary unexpectedly cut off natural gas shipments to Ukraine on Thursday, days after getting assurances from Russian supplier Gazprom that it would get enough deliveries to fill up its own gas storage facilities.Hungary had been sending an estimated 3 million cubic meters of natural gas a day to Ukraine, which has not received any from Russia since June. But FGSZ, Hungary's gas transmission firm, said it suspended the flow to Ukraine indefinitely to ensure pipeline capacity for incoming deliveries as it builds its own reserves.Hungarian Prime Minister Viktor Orban said on Friday on state radio that he had been assured by Gazprom CEO Alexei Miller, whom he met Monday in Budapest, that Hungary would receive the gas supplies it needs to fill up its storage facilities ahead of winter.Orban said Hungary had to be ready in case an escalation of the Russia-Ukraine conflict interrupted flows of natural gas. Hungary gets around 80% of its gas supplies from Russia."We have to prepare for the worst" said Orban, adding that Hungary's storage facilities were nearly 60% full.The Hungarian government signed a deal in January for Russia to build two reactors at Hungary's only nuclear power plant, financing around 80% of expected construction costs with a Russian loan of €10bn.Orban has also said the West was "shooting itself in the foot" with economic sanctions against Russia, which, if they remain in place for a long time, may affect Hungary's nuclear deal.Orban travelled to the Ukrainian city of Beregovo on Friday to visit a Hungarian high school. About 150 000 ethnic Hungarians live in Ukraine, mostly in regions close to Hungary. In his radio interview, Orban reiterated that he supported autonomy for all ethnic Hungarian communities, including in Ukraine.