An alert was declared in Odessa at 11:34 p.m. on Thursday, BTA reported.
"Residents of Odessa and Odesa region should stay in shelters until the alarm goes off. "Threat of drone attack from the Black Sea", announced the chairman of the Odesa Regional Military Administration, Oleg Kiper.
Local Telegram channels report a series of explosions in the city.
Bulgarians in Odesa Region number over 150,000 people and are the third most numerous according to the official census in Ukraine in 2001.
About 50-60 thousand Bulgarians live in the city of Odessa itself. The largest compact Bulgarian population is concentrated in the Bolgrad, Izmail and Belgorodnist regions.