Putin Vows Greater Retaliation after Ukrainian Drone Attacks

"Whoever and no matter how hard he tries to destroy something in our country, he will face many times greater destruction in his own country," Putin was quoted by RIA Novosti as saying on Sunday.

He added that the country will not only restore the damage caused by the attacks but will "move forward at an even faster pace."

On Saturday, eight drone strikes were reported in Kazan, six of which targeted residential buildings.