The United States and Britain already have military trainers in place in Ukraine. Canada, following in the steps of the United States and Britain, will send around 200 troops to Ukraine
The truce had been most fully observed around the rebel-controlled city of Luhansk and near government-held Mariupol on the Sea of Azov.
Ukraine continued to withdraw its weapons on Friday, but the army will remain on high alert in case of a new offensive from the separatists
The Ukrainian army will start withdrawing heavy weapons in east Ukraine
Secretary of State John Kerry on Tuesday sharply dismissed Russia’s “lies” over its role in the deadly conflict in eastern Ukraine.
Kiev says the rebels have launched attacks on villages near Mariupol, a port of 500,000 people, and fears that could be the next separatist target.
Kiev military said government positions had been fired on 112 times by rebels in the past 24 hours.
The temporary truce was declared as German and French leaders pressed forward with a new peace plan to end the crisis in Ukraine.
Kiev's military said five more Ukrainian soldiers had been killed in clashes, while municipal authorities in the rebel-controlled city of Donetsk said 15 civilians had been killed by shelling at the weekend
Rebel leader Alexander Zakharchenko said on Saturday the separatists planned to encircle Debaltseve, which has a population of around 26,000.
"Once again, appeasement encourages the aggressor to greater acts of violence. Time to step up our policy based on cold facts, not illusions," Tusk tweeted
"Russia have just blocked a (Security Council) statement by refusing to include condemnation of recent provocative public statements by the separatists," a council diplomat said
The incident occurred near the town of Volnovakha south of the major industrial city of Donetsk, which is the centre of a nine-month conflict
The deaths, which came as both Ukraine and Russia celebrated Eastern Orthodox Christmas, also coincided with fresh diplomatic efforts to organise a summit in Kazakhstan
More than 4,700 people were killed in 2014 in the conflict, which has provoked the worst crisis in relations between Russia and the West since the Cold War.
In a fresh diplomatic attempt to restore peace, Poroshenko is preparing to meet Russian President Vladimir Putin and the leaders of France and Germany on Jan. 15 in Kazakhstan
Ukrainian authorities and separatists exchanged hundreds of prisoners of war, part of a 12-point plan aimed at ending the pro-Russian uprising in the east of the country.
Putin said the Ukraine crisis should be resolved as quickly as possible and that Moscow's aim was to restore political unity to Ukraine
Kiev military highlighted a decline in the intensity of attacks - to an average of 8-10 incidents of shelling per day from a previous 70-80.
Poltorak said the armed forces planned to spend about $110 million on buying new weapons abroad next year in addition to $365 million spent on domestic arms procurements.
Military spokesman Andriy Lysenko said government forces had come under attack from separatist shells 22 times in the past 24 hours