In recent weeks, Russia has focused on eastern Ukraine - including the Luhansk region.
Now there are reports that the fighting has intensified.
Surrounded cities
The British Ministry of Defense states on Twitter that Russian forces are still trying to surround both the cities of Sevierodonetsk and Lysychansk.
They are the last in the Luhansk region over which Ukraine has continued control.
On Friday night, the governor of the region on Telegram stated that Russian troops had entered Sievjerodonetsk.
He does not believe that Russia can take over the region in the next few days, according to the announcement that Reuters received.
- We will have enough strength and resources to defend ourselves.
But in order not to be surrounded, we may have to withdraw.
Almost all buildings in the city of Sevierodonetsk are damaged.
According to the city's mayor, 60 percent of the city's residential buildings are destroyed.
- The massive artillery shelling does not stop, neither day nor night, says Sievjerodonetsk mayor Oleksandr Striuk according to AP.
The mayor says more than 1,500 people have died since the start of the war.
Of the 100,000 inhabitants who were in the city before the war, between 12,000 and 13,000 remained, according to Oleksandr Striuk.
Taken railway junction
On Friday, Russian separatists say they have taken over Lyman, a major railway junction in Donetsk, north of two cities still under Ukrainian control.
But a spokesman for the Ukrainian Defense Ministry said soldiers were trying to drive out the Russian troops.
At the same time, there are proposals from the Ukrainian side for more advanced weapons from the west in order to stop the Russian advancement in the east.