"The Kiev-led forces are not pulling out heavy weaponry and insist on some kind of a pause," Kelin said in an interview with Rossya-1 television.
"That prompts a certain concern in the OSCE as such a pause could last indefinitely. It will certainly hamper the implementation of the first point of the Minsk agreements," Kelin said.
However, Kiev military spokesman, Andriy Lysenko, said on Tuesday that government troops would only start heavy weaponry pullout if the ceasefire in eastern Ukraine remained stable for at least 48 hours.
Earlier on Wednesday, the self-proclaimed Donetsk People's Republic (DPR), which itself began withdrawing heavy arms from the frontline on Tuesday, reiterated its call for the OSCE to monitor the pullout. DPR Deputy Commander Eduard Basurin promised to provide the organization with safety guarantees.
On Tuesday, Donbas militia pulled back five artillery battalions and an artillery battery. On Wednesday, the DPR plans to withdraw another 180 units of artillery and 18 multiple-launch rocket systems.