Men in camouflage fatigues hustled their way into the headquarters of Ukraine's state energy firm Naftogaz on Wednesday and headed for the management's office, a Naftogaz spokesman said.
Naftogaz was at the heart of a gas dispute with Russia in January that led to gas supply cuts for millions on Europe. It has pledged to pay Russia's Gazprom for February's supplies in the coming days, reported Reuters.
"People in camouflage fatigues pushed aside security, showed no documents. At the moment, they are on the third floor where the management's office is," spokesman Valentyn Zemlyansky said by telephone.