Kiev, Feb 25 (IANS): As many as two explosions were heard on Friday in central Kiev, Ukraine's capital, as the Russian special military operation against Ukraine entered the second day, local media reported.

There was no air raid alert around the time of the blasts, which the local authorities have not yet confirmed, Xinhua reported citing Interfax-Ukraine news agency.

Interior Ministry adviser Anton Gerashchenko wrote in a telegram that he had just heard two powerful explosions, which he later clarified as "attacks by our air defenses on enemy planes or drones," citing operative information.

Mayor Vitali Klitschko tweeted that three people were injured, one was in critical condition, after missile debris hit a residential building.

He also posted a photo showing a building with part of its wall torn down and emergency services present at the scene.

On Thursday, Russian President Vladimir Putin authorised "a special military operation" in Donbas, and Ukraine confirmed that military installations across the country were under attack.

Ukrainian airfields, command posts, naval bases and radar stations were among the facilities destroyed, according to the Russian Defence Ministry.