The authority also urged civilians to leave the towns controlled by the pro-Russian separatists.
"The terrorists attack the population, kidnap citizens and take over private buildings and transport means. We urge the local population to abandon territories seized by the terrorists", said Andrei Lisenko, secretary of Ukraine's Defense and National Security Council.
Over the past weeks fighting has raged around the three rebel-held cities, which were surrounded by government troops.
More than 100 civilians have died in artillery fire since the end of July in the region of Lugansk. The region is on the verge of a humanitarian crisis, without water, electricity and communications and virtually no fuel or fresh food supplies.
Government forces were also besieging the city of Donetsk, where artillery fire has hit several neighbourhoods and there were clashes with the separatists at the entrances to the town.