KHARKIV, Ukraine - Russian strikes killed at least one person, injured others and caused further disruption to power and water supplies on Monday in Ukraine's second city of Kharkiv, officials said, as Ukrainian forces made further advances in the region.

Ukraine's general staff said its soldiers had recaptured more than 20 towns and villages in just the past day from fleeing Russian troops as they press their counter-offensive in the northeast of the country.

A 37-year-old man died and six people including an 18-year-old girl were injured in the strikes, Kharkiv governor Oleh Synehubov said on Telegram.

"Last night's situation is being repeated. Due to the (Russian) strikes... power and water supplies have halted," said the city's mayor, Ihor Terekhov.

A Reuters correspondent said power had been restored at least in central Kharkiv by late afternoon but said loud explosions could again be heard a few km (miles) away.

Some passengers in a Kharkiv underground station waited outside for the metro to reopen, while others scrolled through their phones or tried to catch taxis or other forms of transport to get home.

"We were in the supermarket 'Rost' when we heard two explosions and the light went out," said Yuliia Bezsonova, a Kharkiv resident trying to contact her husband who had been travelling on the metro system.

Moscow denies deliberately striking civilian targets. It has not commented on the reports of strikes on Kharkiv's infrastructure.

(Reporting by Max Hunder and Tom Balmforth; Writing by Gareth Jones; Editing by Hugh Lawson)