A rebel Spring offensive looms as escalation on both sides with their proxies begins.
Ukraine rebel leader Zakharchenko 'wants 100,000 men'
Pro-Russian separatist leader Alexander Zakharchenko says rebels aim to boost their forces to 100,000, as fighting with Ukraine's military intensifies.
The rebels want to push government forces out of the eastern regions of Donetsk and Luhansk and are trying to capture the key town of Debaltseve.
Dozens of people including civilians were killed in clashes and artillery fire at the weekend.
Attempts to agree a truce failed when rebel negotiators did not turn up.
Denis Pushilin, a rebel representative, said rebels would only return to negotiations if the government declared a unilateral ceasefire.
A fragile ceasefire agreed in early September in the Belarusian capital, Minsk, collapsed last month when rebels stepped up their offensive in several areas and seized Donetsk airport.