Ukrainian forces have raised their national flag over a police station in the city of Luhansk which was for months under rebel control, Kiev said on Sunday, in what could be a breakthrough in Ukraine's efforts to crush pro-Moscow separatists, Reuters reported. Ukrainian officials allege though that the rebels are fighting a desperate rearguard action to hold on to Luhansk -- which is their supply route into neighbouring Russia -- and say the flow of weapons and fighters from Russia has accelerated. Andriy Lysenko, a Ukrainian military spokesman, said government forces fought separatists in a neighbourhood of Luhansk city on Saturday and took control of the Zhovtneviy neighbourhood police station. "They raised the state flag over it," Lysenko told a news briefing.