Russian drones have hit the gas transport system in Ukraine's southern Odesa region, a senior Ukrainian official said on Wednesday, an area which contains several pipelines carrying U.S. liquefied natural gas to Ukraine from Greece.

Mykola Kolisnyk, deputy energy minister, did not say what was hit. Data from the Ukrainian gas transit operator showed planned volumes on what is known as the Transbalkan route were largely unchanged.

"In the past 24 hours alone, we have seen the enemy carry out targeted strikes, particularly in the Odesa region, including on the gas transport system and gas transport system's facilities," Kolisnyk told Ukrainian TV.

Russia has sharply increased both the number and intensity of attacks on Ukrainian gas and energy infrastructure in recent months, targeting both gas production facilities and the transmission systems.

Kolisnyk also said sweeping Russian attacks on power supplies had made the provision of electricity more difficult, a day after the Ukrainian government announced more restrictions on power usage.

"The situation in the power system is complicated as a result of ongoing shelling, both massive shelling of the transmission system across all elements of the integrated power system and localized shelling," Kolisnyk said.

Ukrainians in many regions have suffered rolling blackouts and emergency power cuts for weeks this winter. Power was out simultaneously for roughly half of the residents in the capital Kyiv on Tuesday.

"While we are trying to recover from one attack, the enemy launches another," Kolisnyk added.

Prime Minister Yulia Svyrydenko said on Tuesday that the government would introduce more restrictions on power usage and allow additional energy imports as it struggles to repair infrastructure shuttered in Russian strikes.

Ukraine's energy sector is based on nuclear power plants but also uses gas to produce electricity and heat.

On Wednesday, 2.16 million cubic meters of gas were declared for transport on the Transbalkan route used for LNG deliveries, compared to 2.18 million on Tuesday. One of the companies transporting gas via the route also told Reuters that pumping rates would remain unchanged.

Russia's strikes on gas production have deprived Ukraine of more than half of its production volumes and forced it to seek additional imports of over 4 billion cubic meters for the current winter season, the head of Ukraine's National Bank has said.