An explosion has occurred in Odessa, according to the head of the city Gennady Trukhanov.
"An explosion is heard in the city," the mayor said in a statement.
Details are not given.
Currently, air raid sirens are operating in Dnipropetrovsk, Kirovohrad, Mykolaiv, Odessa, Poltava, Sumy and Kharkiv regions of Ukraine.