As soon as Putin declared military operation, explosions in Kyiv heard live on CNN

A CNN journalist in Kyiv reported live explosions on camera early Thursday morning. It happened the moments after Russian President Vladimir Putin declared a "special military operation" in Ukraine.

What is the matter 
U.S. officials have warned that Russia could attempt an attack on Kyiv, to overtook the  Ukrainian government. Not only this but the explosions in other cities across Ukraine were also reported after Putin's remarks.

What did the reporter say?
CNN reporter Matthew Chance after the explosion said,  "This is the first time we've heard anything. It's been absolutely silent in this city throughout the course of tonight and for the past several weeks we've not seen anything at all."

"In fact, I've never heard anything like this in Kyiv for the years that I've been coming here and reporting from here. This is the first time" he added. 

After this Chance was asked to put flak jacket by security after several more explosions were heard during his talk.