Kyiv, Jan 17 (Reuters) - Russia hit gas production equipment in Ukraine in an overnight attack, energy company Naftogaz said on Saturday, adding that it was the sixth attack in a week. "These are targeted strikes on civilian infrastructure to leave Ukrainians without heating and gas during the cold season," the company said on the Telegram app. Ukraine faces its worst wartime energy crisis as its energy sector crumbles under Russian bombardments, bitter cold temperatures, and accumulated damage. (Reporting by Pavel Polityuk, writing by Olena Harmash; Editing by Toby Chopra)