Donetsk: European leaders on Saturday scrambled to ease tensions over claims that Ukrainian forces had destroyed Russian military vehicles as Kiev inched closer to allowing a mammoth aid convoy from Moscow over its border.
While a diplomatic push sought to defuse the rhetoric, deadly shelling pummelled besieged pro-Russian rebel strongholds and a top separatist leader claimed he had received a fresh injection of troops trained "on Russian territory."
Moscow and Kiev`s foreign ministers geared up for an urgent meeting with their French and German counterparts Sunday as Ukraine`s boasts that it had destroyed a small military convoy from Russia ramped up the stakes.
Russia dismissed the claims as "fantasies", but resisted the urge to strike back, as it again denied the persistent allegations from the West that it is arming the rebels.
European heads of state also tried to douse the flames with Ukrainian President Petro Poroshenko holding phone talks with German Chancellor Angela Merkel and meeting Finnish counterpart Sauli Niinistoe, who jetted to Kiev following a face-to-face with Russian leader Vladimir Putin on Friday.
French President Francois Hollande called for Ukraine to show "restraint and good judgement" as it pushed on to oust insurgents after four months of fighting that has killed over 2,100 people and left the region facing a humanitarian disaster.
Three days after a controversial Russian aid convoy pulled up about 30 kilometres from the Donetsk post on the Ukrainian-Russian border, Moscow and Kiev edged closer to a deal to let it pass across the frontier by agreeing on how to inspect the contents of the roughly 300 lorries.
The West and Kiev fear the convoy could be a "Trojan horse" to bolster the flagging pro-Kremlin rebellion in eastern Ukraine or provide Moscow with an excuse to send in the 20,000 troops that NATO says it has amassed on the border.
The International Committee of the Red Cross, which is overseeing the aid delivery, said late Saturday that an agreement was reached on checking the cargo but that "security guarantees" were still needed on how the lorries could cross rebel-held territory.
Russia`s foreign ministry has repeatedly demanded that Kiev cease fire in order for the aid to reach residents of blighted cities in eastern Ukraine who have been stuck for days without water or power.
AFP correspondents at the border heard blasts from the Ukrainian side and saw Moscow`s military hardware rumble along Russian territory close to the frontier.
While Russia has denied funnelling weapons to the rebels, a top separatist leader claimed that troop reinforcements trained across the border had arrived to prop up the ailing insurgency.
Alexander Zakharchenko, prime minister of the self-proclaimed Donetsk People`s Republic, said besides 1,200 personnel "who have received four months of training on Russian territory," there was a fresh injection of firepower consisting of 150 items of military hardware, including tanks.
"They have been brought in at the most crucial moment," he said in a video posted on a rebel website.
In Donetsk, the largest rebel bastion in east Ukraine, local authorities said four civilians were killed in shelling as government troops tightened the vice around the rebels holed up there.
AFP journalists found several houses aflame in Makiyivka, a city adjoining Donetsk, and saw large craters around a residential neighbourhood near a base of rebel special forces.
Human Rights Watch quoted residents fleeing Lugansk -- the rebels second largest stronghold that has seen some of the worst fighting -- as saying that the city was cut off from electricity, gas and cell phone coverage, and that it was difficult to find drinking water and food.
The United Nations says over 285,000 people have fled the fighting in the east.
Ukraine`s security spokesman Andriy Lysenko said Saturday that three soldiers died and 13 were wounded in the past 24 hours.
Poroshenko meanwhile wrote on Twitter that the army has taken over Zhdanivka, a town about 45 kilometres northeast of Donetsk.
A flurry of diplomacy to calm tensions saw Ukraine, Russia, France and Germany agree to get their top diplomats together for a meeting in Berlin on Sunday.
Germany`s Frank-Walter Steinmeier told Bild newspaper that he hoped the talks would help "put an end to violent fighting" in eastern Ukraine and provide the territories with "urgent and necessary aid".
The French presidency suggested that Sunday`s meeting could be a "first step" towards another face-to-face encounter between the heads of state.