ST. PETERSBURG, Oct. 6 – Ukraine could run into gas supply problems given an unusually cold winter because it doesn't have enough gas in underground storage, Gazprom CEO Alexei Miller said.

"I would point out that the heating season in Ukraine last year began on October 17, when volumes [in underground storage] totaled 16.7 billion cubic meters. Now those volumes are just over 15.7 bcm," Miller said at a gas forum in St. Petersburg on Tuesday.