Moscow is taking advantage of the lack of both air defenses in Ukraine and reliable capability to destroy Russian launchers, President Volodymyr Zelenskyy said Thursday following a deadly missile strike on the northeastern city of Kharkiv.

"And this weakness is not ours, but the world's, which has not dared to deal with terrorists in the way they deserve for three years," he said on X.

The death toll in Russian missile strikes on Ukraine's northeastern city of Kharkiv rose to four, with two more people missing, the regional governor said.

Russian troops conducted at least 15 strikes on the city Thursday morning, he added on Telegram.

Russian air defense systems in the southern region of Belgorod destroyed three Olkha and 32 Vampire rockets and three drones launched by Ukraine overnight, the Russian Defense Ministry said Thursday.

The regional governor said earlier that no casualties were reported.