The anti-terrorist operation in east Ukraine will not be stopped, and it will be best if residents leave Donetsk and Luhansk, Andriy Lysenko, a spokesman for the National Security and Defense Council (NSDC), has said.

"The anti-terrorist operation will continue. Peaceful residents should leave the cities of Donetsk and Luhansk just before these are freed," Lysenko said at a Monday briefing.

Each city has humanitarian corridors through which the dangerous zone can be left, he said.

The Ukrainian army needs to continue its advancement in order to prevent militants from re-grouping and getting new hardware and weapons from Russia, he said.