Kyiv was struck early on Saturday as "explosions" were reported in the Darnytskyi district in the eastern part of the Ukrainian capital, Kyiv Mayor Vitali Klitschko said in an online post.
Thick smoke rising from the site on the eastern side of Kyiv could be seen from parts of downtown near the Dnipro River.
Klitschko urged residents to heed air raid sirens and warned those who have fled the capital not to return for now for their safety.
Rescuers and paramedics were on the scene and that victims' details would be released later, he added.
Russia's defence ministry said its forces had struck a military hardware factory in Kyiv, a day after warning of intensified attacks on the Ukrainian capital.
"High-precision long-range air-launched weapons destroyed production buildings of an armaments plant in Kyiv," the ministry said in a statement on Telegram early on Saturday.
The New Arab is providing live updates of what's been happening on the ground and additional analysis on the conflict's significance.