Russian missiles struck targets in the southern regions of Ukraine on Friday, destroying grain terminals and causing casualties.

Odesa's regional governor said Russian forces fired Kalibr cruise missiles from the Black Sea, hitting grain terminals at an agricultural enterprise in the region. Two people were reported injured.

In the region of Zaporizhzhia, authorities posted on social media that four people had been killed in the Russian attacks.

Meanwhile, Russia's defense ministry said on Friday that its Black Sea Fleet had practiced firing rockets at surface targets in a live-fire drill. By conducting the exercise, Russia was apparently intending to keep Ukraine and Western nations in check.

Russia warned earlier in the week that it would regard any ships travelling to Ukraine's Black Sea ports as possibly carrying military cargoes.

The Institute for the Study of War, a US think tank, released its assessment on Thursday that Russia's withdrawal from the deal that allows Ukraine to export grain through the Black Sea -- and intensifying strikes on port and grain infrastructure -- are likely a part of the Kremlin's efforts to extract concessions from the West.

But the institute also says Russia's attempt to achieve economic concession "may undermine the Kremlin's international outreach efforts." It says that blocking Ukraine's exports could threaten food supplies to African nations that Russia has been promising support.