This was reported by Petro Andriushchenko, an advisor to Mariupol’s mayor, on Telegram, according to Ukrinform.
"Urzuf has reported about a series of explosions in Berdiansk. The first three occurred at approximately 11:00-12:00 (temporarily local time, i.e. 10.00-12.00 Kyiv time). Now the sounds of explosions have resumed. The day before in the morning, there were reports from Mariupol about excessive movement of helicopters in the direction of Zaporizhzhia region, later the city reported about the sounds of explosions and small arms. Presumably, this was the work of the occupiers' air defenses," Andriushchenko wrote.
He noted that the situation is being monitored, but suggested this indicates that "something good is happening."
As reported, the invaders are turning Mariupol and nearby villages into a military and logistics hub for the Russian army.