Russian missiles damaged residential buildings and injured six people in Ukraine's second-largest city, Kharkiv, early on Wednesday, Governor Oleh Synehubov said on Telegram.

The attack damaged three residential buildings, two offices, three non-residential buildings and a gas pipeline in the central district of the city, according to the governor's statement.

Some 568 windows and 33 cars were damaged, Synehubov said.

The city's mayor, Ihor Terekhov, told Ukranian TV that two S-300 missiles were used in the attack but did not cause significant damage to the residential areas of the city.

Russia's RIA state news agency reported on Wednesday, citing unnamed sources within Russian forces, that their attack hit soldiers' quarters in Kharkiv where Ukrainian military personnel were stationed.

Reuters could not independently verify the reports.

Terekhov said the work to repair the gas pipeline continued as the city raced to restore gas supply to the impacted part of the city on Wednesday morning. REUTERS