Ukrainian law enforcers will unilaterally cease fire in eastern regions in order to give members of illegal armed units a chance to disarm themselves and Russian mercenaries wishing to leave the country to do so, Ukrainian President Petro Poroshenko said.

"The [president's peace] plan starts with my order of unilateral ceasefire. We should gain support to the president's peace plan by all the participants in the Donbas events immediately after that. Very quickly," Poroshenko told reporters in Kyiv on Wednesday.

The ceasefire will be very brief and during this period the illegal armed groups must be disarmed and order must be restored in the region, he said.