DONETSK, Ukraine - Pro-Russian rebels and the Ukrainian military accused each other Saturday of breaking a tenuous Kremlin-backed truce only hours after it came into force across the war-battered east.
Although the situation overall appeared to be calm, the rival claims underscore the fragility of the deal that aims to end five months of bloodshed but contains no framework for a political solution to an insurgency still threatening to tear apart Ukraine.
"The ceasefire's terms are not being observed," Vladimir Makovich, a leading member of the "parliament" established by the self-proclaimed Donetsk People's Republic, told AFP.
He said Ukrainian units had fired several missiles towards rebel positions on the outskirts of the main insurgent bastion of Donetsk just three hours after the truce came into effect at 1500 GMT on Friday.
But Ukraine's National Security and Defence Council spokesman Andriy Lysneko told reporters the military had recorded a "series of provocations by the rebels".
The 12-point pact signed in the Belarussian capital Minsk is the first backed by both the Kremlin and Kiev since bands of Russian-speaking militias seized a string of government buildings across Ukraine's industrial heartland in early April.
But with Western leaders still deeply suspicious of Russia's intentions, the US and EU have agreed to beef sanctions against Moscow, and NATO approved a rapid reaction force aimed at reassuring jittery eastern European states.
The standoff over Ukraine set off the most serious crisis between Russia and the West since the Cold War.
"This decision sends a clear message - NATO protects all allies at all times," outgoing chief Anders Fogh Rasmussen said at the alliance's summit in Wales, describing the Ukraine crisis as a "wake-up call".
Russia warned it would react if the EU imposes more sanctions, accusing Brussels of supporting the "party of war" in Kiev.
Under the terms of the truce brokered by the OSCE European security body, both sides should start pulling back from major flashpoints and exchanging prisoners on Saturday.