The United States says it will supply Ukraine with depleted uranium ammunition as part of its additional military aid.
US Secretary of State Antony Blinken announced a new assistance package during his visit to Kyiv on Wednesday. The package, worth more than 1 billion dollars, includes depleted uranium rounds that can pierce tanks and armor.
Blinken said the new assistance will help sustain Ukraine's ongoing counteroffensive and build more momentum.
Britain has already supplied Ukraine with depleted uranium munitions.
Russia reacted sharply to Washington's decision.
Russian Deputy Foreign Minister Sergey Ryabkov accused the US of not only taking an escalatory step but also disregarding the environmental consequences in a combat zone.
Meanwhile, the Ukrainian Air Force said on Thursday that Russia carried out drone assaults in the southern region of Odesa and elsewhere.
The Russian military has been repeatedly launching attacks on the region that serves as an alternative route for exporting Ukrainian farm products instead of through the Black Sea.
Russia's defense ministry said on Thursday that Ukraine conducted drone attacks on three Russian regions. It said the drones were shot down near Moscow, in the southern region of Rostov and the western region of Bryansk. One person was reportedly injured in Rostov.