Kyiv says Ukrainian government forces are preparing to withdraw artillery and heavy armored vehicles within a proposed 30-kilometer buffer zone.
Ukrainian military spokesman Andriy Lysenko said on September 22 that Kyiv has made the decision after detecting a lessening of fire in recent hours from Russian-backed separatists and no firing from Russian territory.
He said the rebels had also begun their withdrawal of heavy artillery, although it was "not as massive as we expected."
Representatives of Ukraine and the pro-Russian separatists agreed on September 19 to pull artillery and other heavy equipment 15 kilometers back on either side of their battle-line to create a buffer zone.
However, the Ukrainian military had said on September 21 it would not go ahead with setting up the proposed buffer zone after accusing the rebels and Russian troops of continuing to shoot at government forces.
Moscow denies it has sent forces into eastern Ukraine or armed the rebels, an assertion that the United States and NATO have rejected as false.
The September 19 agreement built on a September 5 cease-fire deal that also called for prisoner exchanges and other steps to end the conflict in eastern Ukraine, which has killed more than 3,000 people in eastern Ukraine since April.
The Kremlin said Russian President Vladimir Putin discussed the implementation of the peace plan with senior officials at a meeting of his Security Council on September 22.
In accordance with the September 5 agreement, Ukraine's parliament has passed laws proposed by President Petro Poroshenko granting limited self-rule to the rebels in the Donetsk and Luhansk regions for three years, plus an amnesty for some separatists fighting government forces.
The cease-fire has been marred by numerous violations, but Poroshenko said on September 21 that the conflict in eastern Ukraine cannot be solved militarily.
"The more Ukrainian army battalions or brigades are brought up, the more troops there are from the Russian Federation," Poroshenko said in a question-and-answer session with Ukrainian journalists.
He also said Ukraine had lost 65 percent of its military hardware on the front lines during fighting in the Donetsk and Luhansk regions.
With reporting by Reuters and Interfax