Several explosions hit the center of Kyiv on Monday morning, mayor Vitali Klitschko said, with a Reuters witness reporting a cloud of black smoke rising from buildings.

"Several explosions in the Shevchenskivskyi district - in the centre of the capital," Klitschko said on the Telegram messaging app. "Details later."

Photo: Smoke rises over Kyiv after Russian missile strikes on the Ukrainian capital's outskirts, as Russia's attack on Ukraine continues, in Kyiv, Ukraine  REUTERS/Vladyslav Sodel