Ukrainian government forces said they had suspended combat operations as a "Day of Silence" began in the war-torn east on Tuesday, marking an effective ceasefire on the front line of the conflict with separatist rebels.
A Ukrainian military spokesman added that "if separatists attack, we will fire in response."
The pro-Russian separatists who hold parts of Ukraine’s Donetsk and Luhansk provinces have said they would also comply.
Ukrainian President Petro Poroshenko announced the September 9 truce plan, saying it was included in a cease-fire deal signed in Minsk on September 5.
He said a new round of peace talks would probably be held on December 9, but several offocials and separatist leaders have said they are likely to be held later in the week, probably on December 12.
Russian Foreign Minister Sergei Lavrov said the talks would be held "in the coming days."