KHARKIV, Ukraine -- A bomb has been detonated under a national flag memorial in Ukraine's eastern city of Kharkiv.



The local prosecutor's office says the incident took place at 3.40 a.m. on April 7.



The explosion damaged part of the memorial and shattered windows at the nearby Medical University building.



Nobody was hurt in the blast.



No group claimed responsibility for the attack.



A series of bomb blasts have hit Kharkiv and another government-controlled eastern Ukrainian city, Odesa, in recent months.



Most of the attacks seemed to target organizations with ties to soldiers battling pro-Russian separatists in Ukraine's east.



Ukrainian authorities blamed the explosions on Russia and the rebels who hold parts of Donetsk and Luhansk regions.



Kharkiv and Odesa are seen as prizes coveted by the separatists.



With reporting by UNIAN