Pro-Russian separatists brought reporters today to witness the withdrawal of heavy weapons from the front line in east Ukraine under a ceasefire deal.
However, Ukraine said the rebels were using the cover of the truce to reinforce for another advance.
Fighting has eased in eastern Ukraine in recent days, raising hope that a ceasefire due to start on 15 February can finally take effect.
Rebels had initially ignored the truce when they stormed a government-held town last week.
Since taking the railway hub of Debaltseve in one of the worst defeats of the war for Kiev, the Moscow-backed rebels have indicated they now want to abide by the truce.
Kiev says the rebels are still shooting, which they deny.
Journalists in rebel-held territory watched ten trucks carrying howitzers roll through Makiyvka, near rebel-held Donetsk.
Rebels said the guns were on their way from Donetsk towards Amvrosiyvka, a town far from the front and close to the Russian frontier.
Near Amvrosiyvka, Reuters journalists saw a second convoy carrying 14 howitzers, also heading towards the Russian border.
Rebel commander Eduard Basurin said there were no plans for any further military advances. "That's it. We are going no further," he said.
He said the rebels still aimed to gain control of the entire territory of east Ukraine's two rebellious provinces, including the government-held port of Mariupol, but would seek this through "negotiations with the Ukrainian side".
Mr Basurin said today that 100 artillery pieces had been pulled back during the course of the day, and the rebels intended to complete the entire withdrawal of all heavy weapons as required under the truce, despite an announcement by Kiev that it was not yet ready to start.
"However many there are, they will all be withdrawn. The mission of the OSCE will monitor all the sectors and confirm whether or not we are lying," he told reporters in Donetsk, referring to the European security body tasked with verifying the truce.
The Kiev military said rebel assertions they were pulling back guns were "empty words".
"On the contrary, the terrorist groups, making use of the ceasefire period, are reinforcing their units and building up ammunition."
Meanwhile, British Prime Minister David Cameron has announced that up to 75 British military personnel will deploy to Ukraine next month to provide advice and training to government forces.
The UK servicemen will be based well away from the areas of conflict in the east of the country, and will offer support with medical, intelligence, logistics and infantry training.
There has been no decision to move to supplying lethal weaponry to the Kiev government.
Moscow lying 'to my face,' says Kerry
US Secretary of State John Kerry has accused Russian leaders of lying "to my face" about Moscow's involvement in the conflict in Ukraine and denounced what he called Russia's "propaganda."
He refused however to say publicly whether he was in favour of sending US weapons to Kiev to help the Ukrainian military battle the pro-Russian rebels in the east.
"Russia has engaged in a rather remarkable period of the most overt and extensive propaganda exercise that I've seen since the very height of the Cold War," Mr Kerry told US lawmakers.
