As pro-Russian separatists maneuver into position outside Slaviansk, gunfire echoes in the distance.

Ukraine's interior minister said on Monday that separatists had ambushed Ukrainian forces, leaving an unknown number killed.

The fighting there is getting closer to the separatists' stronghold in the city.

In Kiev, officials admit that they are struggling in the fight.

(SOUNDBITE) (Ukrainian) UKRAINIAN SECURITY SERVICE (SBU) SPOKESPERSON, MARYNA OSTAPENKO, SAYING:

"The intensity of pro-Russian forces is not decreasing. The situation remains tense and separatists are strengthening their activities towards the destabilization of the situation in Ukraine's east."

Back in Slaviansk, residents are trying to resume normal lives.

However, with heavy fighting on their doorsteps, one resident was determined the city would defend itself against Ukrainian forces.

(SOUNDBITE) (Russian) SLAVIANSK RESIDENT, ALEXEI, SAYING:

"If they storm, honestly