The electricity supply has been fully restored in three of the affected regions, according to a presidential aide

Blackouts allegedly caused by Russian strikes on the Ukrainian power grid were partially dealt with overnight, according to President Vladimir Zelensky’s deputy chief-of-staff.

In a Telegram post, Kirill Timoshenko reported the full restoration of electricity supplies in the Ukrainian cities of Sumy, Dnepropetrovsk and Poltava. Grid capacity in Kharkov region, which was the scene of a successful Ukrainian counter-offensive last week, was at 80% on Monday morning, according to the official.

The Mayor of Kharkov, Igor Terekhov, said on Monday morning that the city’s subway and trolleybus systems were back online and that the water supply would be fully restored during the day. Electric-powered transport was paralysed during the Sunday outage.

Kiev blamed the blackouts in several of its regions on Russian missile attacks targeting power stations and key nodes of the transmission grid. The Russian military has neither confirmed nor denied carrying out such attacks.

READ MORE: Ukraine suffers massive blackout after ‘Russian strikes’

The purported Russian military action on Sunday followed Ukraine’s counter-offensive in the north of the country. Last week, Kiev forced Russian troops to leave a swath of previously captured territory in Kharkov region.

Kiev called it a major success for its military and a harbinger of further victories on the battlefield. Moscow has described the loss of territory as a temporary setback, necessary to win time for regrouping Russian troops.