Pro-Russian separatists and Ukraine's National Guard are blaming each other for failing to establish the corridor which would allow people to flee the Ukrainian city of Mariupol.
It's the second day in a row a ceasefire's collapsed.
More than 2-thousand people have reportedly been arrested in dozens of Russian cities in protest at the invasion.
That's according to an independent monitoring group there.
It coincides with Ukraine's president pleading with Russian people to take action - saying it's "not too late" for them to help stop this war.
Meanwhile, Vladimir Putin and France's president Emmanuel Macron, have spoken with each other by phone for an hour and 45 minutes over the crisis.