A bitter gas price row with Russia's energy giant Gazprom last winter led to shortfalls in gas supplies to Ukraine amid Arctic temperatures in January, prompting fears that a similar situation could develop again this year.
"Ukraine has pumped 6.5 billion cubic meters of natural gas into underground storage facilities, the Naftogaz press service said.
The company said it was planning to reserve 16.4 billion cu m in 2006 and that the plan was likely to be implemented given dynamic pumping rates in June and early July.
Naftogaz said Ukraine had imported 5.2 billion cu m of gas at a price of $95 per 1,000 cu m in June 2006.
But Gazprom said last week the situation with Ukraine's storage of natural gas remained tense, as Naftogaz's debt to Rosukrenergo, a trader handling Russian and Central Asian natural gas 50% owned by Gazprom, exceeded $650 million.
Under an agreement that Russia and Ukraine signed on January 4, Ukraine imports a mixture of Russian and Turkmen natural gas at $95 per 1,000 cubic meters.
