STORY: His comments were made to a local affiliate of Radio Free Europe/Radio Liberty.
Earlier on Tuesday, the Russian-backed Donetsk People's Republic said in a post on the Telegram messaging service that its forces had taken control of the town and replaced the Ukrainian flag with a Russian flag.
Reuters journalists saw soldiers outside a local administrative building where a Russian flag was flying.
Svitlodarsk is around 50 miles southwest of Sievierodonetsk - the focus of Russian attacks in recent days.
Russia is attempting to seize the separatist-claimed Donbas' two provinces, Donetsk and Luhansk, and trap Ukrainian forces in a pocket on the main eastern front.