Ukrainian officials say both government troops and rebels have started withdrawing heavy artillery in the east of the country.
The development comes after a deal was signed over the weekend to further the cease-fire, calling for both sides to halt advances and create a buffer zone.
Colonel Andriy Lysenko is the spokesman for Ukraine's National Security and Defense Council.
"Ukrainian military units have begun implementing the Minsk agreements from September 5th and 19th. We have stated our preparedness to withdraw all heavy
weapons - 15 - from the frontline. This kind of weapon includes all artillery and tanks with a calibre of 100 millimetres and over."
Under the deal, each party must pull back heavy artillery and set up a 30 kilometers wide buffer zone.
The deal came after a truce signed earlier this month was hampered by violations which led to at least 39 deaths.
As of Monday, clashes were still reported around the cities of Donetsk and Mariupol.
Ukraine's parliament passed a bill last week, granting three-year self-rule to parts of the Donetsk and Luhansk regions.
