Ukrainian law enforcement units will encircle Sloviansk to liquidate the armed opposition and regain full control over the state border in eastern regions, Ukrainian President Petro Poroshenko said.

"We are taking resolute steps and conducting successful operations towards the restoration [of control] over the state border," the president told reporters in Kyiv on Wednesday.

"We will do our best today to encircle Sloviansk; we are moving on and the circle is tightening in order to liquidate the militants led by the so-called Shooter [defense minister of the self-proclaimed Donetsk People's Republic Igor Girkin (Strelkov)] who are resisting Ukrainian servicemen with arms," Poroshenko said.

The president said he was maintaining permanent contact with senior officials of the Ukrainian Defense Ministry and the anti-terrorist operation command.

"Conferences are held practically every day in the Defense Ministry and at my [office] and operations are thoroughly planned. When the Go order is given we try to do our reconnaissance well and to properly equip our fighters so that we avoid civilian and army casualties. When they try to move on without an order, we see what we saw last night. No one is going to tolerate Makhnovism in the Ukrainian army," the president said.

It is important to assign trained, well equipped and well armed fighters on combat missions, he said. "Now we need not just heroism [although we need it very much], not only patriotism but also strict military discipline and cohesion with other units of the Armed Forces, reconnaissance, interaction and clearly defined tasks," Poroshenko said.