KYIV  - Ukraine's national power grid operator said on Tuesday the damage dealt to Ukrainian power generating facilities by Russian missile attacks was "colossal" but dismissed the need to evacuate civilians.

Volodymyr Kudrytskyi, chief executive officer of Ukrenergo, told a briefing that Ukrainians could face long power outages but that the grid operator wanted to help provide the conditions for people to remain in the country through winter.

Practically no thermal or hydroelectric stations had been left unscathed by the Russian attacks, he said.

"The scale of destruction is colossal," Kudrytskyi said. "In Ukraine there is a power generation deficit. We cannot generate as much energy as consumers can use."

He said a short cold snap was expected from Wednesday but that temperatures would rise again after that, providing an opportunity to stabilise the power generating system.

Ukraine had enough fuel reserves after building them up before Russia's Feb. 24 invasion, he said, and was working hard to repair damaged infrastructure but was hoping to secure some spare parts abroad.

Asked about proposals by some officials to evacuate some cities worst hit by energy shortages, he said such calls were "inappropriate."

(Reporting by Pavel Polityuk, Editing by Timothy Heritage)