Powerful explosions were heard in the early hours on Friday in Ukraine's capital, Kyiv, and a number of other cities across the country, local media reported.
Overnight, air raid sirens were going off over all of Ukraine.
Explosions were also heard in the southern city of Kherson, the eastern city of Kharkiv and in Ukraine's western city of Ivano-Frankivsk.
There has been no official confirmation of the explosions.
Reuters could not immediately verify the reports.
