They're in place around 5 key areas which have subjected to heavy shelling in recent days.
Ukraine's deputy prime minister says safe routes are operating in some cities and officials are looking to get as many civilians away from danger as possible.
The United Nations says more than 2-point-1 million refugees will have fled the country by the end of the day.
It expects that number to grow.
Earlier
The United States say a Polish plan to provide fighter jets to Ukraine is 'not tenable.'
It suggested passing them on through a US-NATO base in Germany.
But Washington's worried about escalating the situation by sending planes from one of their sites directly into airspace that's contested with Russia.
Meanwhile, new safe routes are opening-up around now aimed at getting more civilians out of some heavily bombed Ukrainian cities.
Around 5-thousand did manage to escape from Sumy in the north-east yesterday - but a ceasefire didn't hold in Mariupol in southern Ukraine.
The Red Cross describes the situation there as apocalyptic – with people running out of electricity, food and drinking water.
