Three explosions have been reported in Mariupol, a southern Ukrainian city occupied by Russia, a Ukrainian official said Saturday.
One of the explosions was caused by Russian air defense systems in Nikolske, a settlement just northwest of the city, Petro Andriushchenko, an adviser to the city's Ukrainian mayor, wrote on Telegram.
Smoke can also be seen rising from the side of a railway station in the area, according to Andriushchenko.
Pro-Russian officials have in recent days accused Ukraine of striking Mariupol, a city it once fiercely defended. Andriushchenko has commented on the blasts online, but the Ukrainian military has not officially claimed responsibility for the attacks.
CNN cannot independently verify battlefield developments.