Ukraine said on Sunday it will not agree to a buffer zone and pull back troops from the frontline with pro-Russian separatists until violations of a two-week-old cease-fire are stopped.
The Ukrainian military accused separatists and Russian troops on Sunday of continuing to shoot at government forces despite a September 5 cease-fire.
Ukraine's warring sides agreed on Friday to withdraw artillery and other heavy weapons to the outer limits of a 30-kilometer (19-mile) buffer zone, building on the cease-fire in a conflict in eastern Ukraine that has killed more than 3,000 people.
Military spokesman Andriy Lysenko said the pro-Russian separatists and Russian troops were continuing to target the positions of government forces.
“In the last 24 hours we have lost two Ukrainian soldiers, eight have been wounded,” he told reporters on Sunday.
Asked about the buffer zone, he said: “One of the main points of the agreement is the cease-fire, then other points follow.
“At the moment, the first point has not been fulfilled so we are not talking about the other points. If there is to be a withdrawal of forces, then it should be synchronized together with the withdrawal of Russian forces,” he said.
The heaviest gunfire Sunday erupted around the separatist stronghold in Donetsk.
Lysenko said separatists had carried out a further attack on the government-held international airport of Donetsk, the east's main industrial hub. The rebels hold the city of Donetsk.
He said 40 separatist fighters had been killed in “defensive” fire by Ukrainian forces. There was no independent confirmation of this figure.
Russians march in protest
Also Sunday, thousands of Russians marched in protest against the armed conflict in Ukraine in the first major anti-war rally since the start of the standoff between Kyiv and pro-Russian rebels.
The armed conflict, which Kyiv and the West blame on Russia's support of the separatist armed groups in eastern Ukraine, has killed more than 3,000 people since April, although this month's cease-fire has brought a relative calm.
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The organizers of “The March for peace” said over 50,000 people took to the streets in Moscow alone on Sunday afternoon to deliver a strong message to President Vladimir Putin: stop the war. Protests were also held in other cities across Russia.
Moscow police said 5,000 people attended the march. Protesters often accuse police of underestimating the size of anti-Kremlin rallies, and opposition protests also get limited coverage on state TV.
A Reuters correspondent said at least several thousand protesters packed Moscow's central Tverskaya street on Sunday afternoon amid increased police presence, which included a helicopter overseeing the area.
Cease-fire 'in name only'
On Saturday, NATO's top military commander, U.S. Air Force General Philip Breedlove, said he is hopeful the new agreement to create a buffer zone between Ukrainian government troops and pro-Russian separatists will calm the conflict.
However, Breedlove said the current situation was "not good," with Russian troops still inside Ukraine.
Breedlove said the cease-fire signed earlier this month was "in name only" with violence levels in the past few days as high as they were before the truce.
Under the new pact reached in Minsk Saturday, Ukrainian troops and the separatists must each pull back their artillery 15 kilometers from the front line to form a 30-kilometer buffer zone.
The so-called "Minsk Memorandum" also requires both sides to withdraw all foreign "mercenaries" from the conflict zone in eastern Ukraine. Moscow has denied accusations by Ukraine and Western nations that Russian troops have been fighting alongside the rebels.
But, Breedlove said Russian forces were in eastern Ukraine, even though their numbers have decreased.
He said some have returned to the Russian side of the border, but have not returned home and "are still available to bring their military force to bear on Ukraine should it be desired."
Russia's ambassador to Ukraine told reporters after the Minsk meeting Saturday that both sides have employed foreign mercenaries.
Saturday's agreement, negotiated by representatives of Ukraine, Russia, the separatists and the Organization for Security and Cooperation in Europe (OSCE), aims to reinforce the September 5 cease-fire, which has been repeatedly violated.