The Russian military used incendiary or phosphorous bombs against the defenders of Azovstal steel plant for the first time on Sunday, Ukrainian media Ukrinform reported, citing Mariupol mayor's adviser Petro Andryushchenko.

The information was not immediately verifiable by the Russian side.  

On the other hand, the governor of the Belgorod region in Russia, Vyacheslav Gladkov, said the Belgorod village of Sereda in Russia came under fire from Ukraine, and one civilian was injured.