The phone conversation comes as the death toll hit 35 following a week of clashes between Ukrainian troops and Russian-backed insurgents in a level of bloodshed unseen in the eastern war zone since 2015.
The violence erupted as Trump seeks to build a friendship with Russia's Vladimir Putin with some analysts linking the escalation to the potential thaw in ties.
The scheduled call -- which will take place in the evening -- will see Ukrainian President Petro Poroshenko seeking to win assurances of Washington's continued diplomatic and non-lethal military support.
Russia and Ukraine along with the rebels on Wednesday signed up to calls for a ceasefire and the withdrawal of heavy weapons from the flashpoint town Avdiivka by Sunday.
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But the demand for the shooting to stop has not halted the violence and so far there has been little sign of the big guns being pulled back around the Kiev-held industrial town of 25,000 at the centre of the fighting.
AFP correspondents on site said the night and morning passed relatively calmly compared to previous ones.
But the Ukrainian army said one of its soldiers had been killed in the area.
Most residents of this blue-collar town work in a major coke plant that has been heavily damaged by the shelling.
The town remained without electricity yesterday and with only sporadic power supplies to heat homes against the freezing winter temperatures and limited supplies of water.
The giant plant provides electricity for much of the region and has been the target of previous deadly rebel attacks.
Plant spokesman Dmytro Murashko told AFP that work brigades would try again Saturday to repair broken power lines after shelling halted their earlier efforts.
The call to withdraw heavy weapons was made under the coordination of mediators from the Organisation for Security and Cooperation in Europe (OSCE).