KHARKIV, Ukraine (Reuters) - Russian strikes on a crowded DIY hardware store in the Ukrainian city of Kharkiv on Saturday killed at least two people, wounded many more, and triggered a huge blaze that fire crews were battling to contain, regional officials said.

Oleh Syniehubov, Kharkiv regional governor, said via the Telegram messaging app that two guided bombs had hit the DIY hypermarket in a residential area of the city. He said 24 people were injured along with the two confirmed deaths.

Kharkiv Mayor Ihor Terekhov said many people were unaccounted for but gave no immediate figures. Officials said up to 200 people could have been in the hypermarket at the time of the strikes.

"The attack targeted the shopping centre, where there were many people - this is clearly terrorism," Terekhov said.

Reuters video footage showed huge clouds of dark smoke rising into the sky from the site with firefighters' vehicles and rescuers heading to the scene.

Rescuers, medics and journalists rushed away from the building and lay flat on their stomachs, fearing the possibility of a second strike - a common feature of Russia's recent attacks.

Ukraine's second-largest city lying 30 km (18 miles) from the Russian border, Kharkiv has been the target of many weeks of Russian attacks. Russian troops also staged an incursion into northern areas of Kharkiv Region earlier this month.

Witnesses described panicked scenes at the shopping centre.

"I was at my workplace. I heard the first hit and ... with my colleague, we fell to the ground. There was the second hit and we were covered with debris. Then we started to crawl to the higher ground," said Dmytro Syrotenko, who had a large gash to his face.

The 26-year-old told Reuters he was taken to safety by a rescue worker who helped him, several colleagues, and shoppers.

Immediately after the strike, Ukrainian President Volodymyr Zelenskiy issued a fresh plea for more air defence to be able to protect the city of about 1.3 million people.

Moscow denies deliberately targeting civilians, but thousands have been killed and injured during its 27-month full-scale invasion of Ukraine.

(Additional reporting by Olena Harmash; Editing by Gareth Jones and Ana Nicolaci da Costa)

By Max Hunder