The governor of the eastern Ukrainian region of Luhansk says Russia has used white phosphorus bombs in that area.

The governor posted the message on social media on Thursday. Phosphorus bombs can seriously harm human bodies.

Ukraine's public broadcaster has quoted Luhansk officials as saying that at least four people were killed, and six individuals were injured, in Russian military attacks.

Two children were reportedly among those killed. The broadcaster says rockets and phosphorus bombs may have been used.

Ukrainian President Volodymyr Zelenskyy also told those attending the NATO summit on Thursday that Russia's military had used white phosphorus bombs earlier in the day. He said adults and children were killed.

White phosphorus bombs are not designated as chemical weapons. But victims suffer serious burns. International critics say the weapons are inhumane.