Ukrainian policemen patrol a street near the new line of contact in Katerynivka, Luhansk region, eastern Ukraine, Saturday, Nov. 2, 2019. The weaponry pullback finally began after President Volodymyr who won office in April on a pledge to end the war, visited the area around the eastern village of Zolote and confronted armed veterans who came there to try to hamper the weapons pullback. (AP Photo/Evgeniy Maloletka)

MOSCOW (AP) — Ukraine's military has postponed a second stage of a weapons pullback in the country's conflict-ridden east, drawing criticism from the Kremlin's envoy to a group trying to help end the fighting.

The military said the pullback near the town of Petrovske, which was tentatively set for Monday, could not be conducted because of recent cease-fire violations.

Ukrainian forces and Russia-backed separatists have fought since 2014 in a war that has killed more than 13,000 people. A Ukrainian heavy weapons pullback elsewhere in the east last week raised hopes that a stumbling peace process was advancing.

Boris Gryzlov, Russia's representative to the Contact Group of Ukraine, Russia and the OSCE, says "we are once again convinced that the main reason for the stalling of the .... process is the position of Kyiv."

Ukrainian policemen patrol a street near the new line of contact in Katerynivka, Luhansk region, eastern Ukraine, Saturday, Nov. 2, 2019. The weaponry pullback finally began after President Volodymyr who won office in April on a pledge to end the war, visited the area around the eastern village of Zolote and confronted armed veterans who came there to try to hamper the weapons pullback. (AP Photo/Evgeniy Maloletka)
Ukrainian serviceman guard a checkpoint near the new line of contact in Zolote, Luhansk region, eastern Ukraine, Saturday, Nov. 2, 2019. The weaponry pullback finally began after President Volodymyr who won office in April on a pledge to end the war, visited the area around the eastern village of Zolote and confronted armed veterans who came there to try to hamper the weapons pullback. (AP Photo/Evgeniy Maloletka)
Barbed wire at the new line of contact in Zolote, Luhansk region, eastern Ukraine, Saturday, Nov. 2, 2019. The weaponry pullback finally began after President Volodymyr who won office in April on a pledge to end the war, visited the area around the eastern village of Zolote and confronted armed veterans who came there to try to hamper the weapons pullback. (AP Photo/Evgeniy Maloletka)
Ukrainian servicemen guard a checkpoint near the new line of contact in Zolote, Luhansk region, eastern Ukraine, Saturday, Nov. 2, 2019. The weaponry pullback finally began after President Volodymyr who won office in April on a pledge to end the war, visited the area around the eastern village of Zolote and confronted armed veterans who came there to try to hamper the weapons pullback. (AP Photo/Evgeniy Maloletka)
Ukrainian military servicemen, members of Joint Center for Control and Coordination (JCCC) mission talk with OSCE monitors near the new line of contact in Katerynivka, Luhansk region, eastern Ukraine, Saturday, Nov. 2, 2019. The weaponry pullback finally began after President Volodymyr who won office in April on a pledge to end the war, visited the area around the eastern village of Zolote and confronted armed veterans who came there to try to hamper the weapons pullback. (AP Photo/Evgeniy Maloletka)
Ukrainian servicemen guard a checkpoint near the new line of contact in Zolote, Luhansk region, eastern Ukraine, Saturday, Nov. 2, 2019. The weaponry pullback finally began after President Volodymyr who won office in April on a pledge to end the war, visited the area around the eastern village of Zolote and confronted armed veterans who came there to try to hamper the weapons pullback. (AP Photo/Evgeniy Maloletka)
Ukrainian military vehicles are seen through a bus window near the new line of contact in Katerynivka, Luhansk region, eastern Ukraine, Saturday, Nov. 2, 2019. The weaponry pullback finally began after President Volodymyr who won office in April on a pledge to end the war, visited the area around the eastern village of Zolote and confronted armed veterans who came there to try to hamper the weapons pullback. (AP Photo/Evgeniy Maloletka)
A Ukrainian serviceman watches from his position at the new line of contact in Zolote, Luhansk region, eastern Ukraine, Saturday, Nov. 2, 2019. The weaponry pullback finally began after President Volodymyr who won office in April on a pledge to end the war, visited the area around the eastern village of Zolote and confronted armed veterans who came there to try to hamper the weapons pullback. (AP Photo/Evgeniy Maloletka)
Ukrainian servicemen set a trench at the new line of contact in Zolote, Luhansk region, eastern Ukraine, Saturday, Nov. 2, 2019. The weaponry pullback finally began after President Volodymyr who won office in April on a pledge to end the war, visited the area around the eastern village of Zolote and confronted armed veterans who came there to try to hamper the weapons pullback. (AP Photo/Evgeniy Maloletka)
A Ukrainian serviceman walks up from a trench at the new line of contact in Zolote, Luhansk region, eastern Ukraine, Saturday, Nov. 2, 2019. The weaponry pullback finally began after President Volodymyr who won office in April on a pledge to end the war, visited the area around the eastern village of Zolote and confronted armed veterans who came there to try to hamper the weapons pullback. (AP Photo/Evgeniy Maloletka)
Ukrainian servicemen set a trench at the new line of contact in Zolote, Luhansk region, eastern Ukraine, Saturday, Nov. 2, 2019. The weaponry pullback finally began after President Volodymyr who won office in April on a pledge to end the war, visited the area around the eastern village of Zolote and confronted armed veterans who came there to try to hamper the weapons pullback. (AP Photo/Evgeniy Maloletka)
A Ukrainian serviceman digs a trench at the new line of contact in Zolote, Luhansk region, eastern Ukraine, Saturday, Nov. 2, 2019. The weaponry pullback finally began after President Volodymyr who won office in April on a pledge to end the war, visited the area around the eastern village of Zolote and confronted armed veterans who came there to try to hamper the weapons pullback. (AP Photo/Evgeniy Maloletka)
Ukrainian servicemen set a trench at the new line of contact in Zolote, Luhansk region, eastern Ukraine, Saturday, Nov. 2, 2019. The weaponry pullback finally began after President Volodymyr who won office in April on a pledge to end the war, visited the area around the eastern village of Zolote and confronted armed veterans who came there to try to hamper the weapons pullback. (AP Photo/Evgeniy Maloletka)
Ukrainian President Volodymyr Zelenskiy, left, and NATO Secretary General Jens Stoltenberg pose for a photo during their meeting in Kyiv, Ukraine, Thursday, Oct. 31, 2019. Ukrainian President Volodymyr Zelenskiy says that government troops will begin the pullback in a second location in eastern Ukraine next week if a cease-fire there persists. (Mykola Lazarenko/Ukrainian Presidential Press Office via AP)