India increased imports of Saudi oil in December as payment problems drove its Russian oil buys to an 11-month low, with at least five cargoes of the sweet Sokol variant heading to other locations, data from vessel tracking agencies showed. Indian Oil Corp (IOC) which was set to get the Sokol oil, had to withdraw from its inventory and buy from the Middle East to make up the shortfall, sources told Reuters last month. Top refiner IOC is the only state-run firm with an annual deal to buy a variety of Russian grades, including Sokol, from Russian oil major Rosneft.