Kiev: Ukraine lost eight soldiers Wednesday in a dramatic spike in fighting with pro-Russian gunmen that further imperilled a truce Washington`s top European envoy is desperately trying to salvage in Kiev.
Separatist rebels also reported the death of two fighters and a civilian in shelling across the eastern industrial heartland of the former Soviet nation that took a decisive tilt toward the West more than a year ago.
The resulting crisis has created waves of concern across Europe and sparked the sternest confrontation between Moscow and the West since the Cold War.
The Kremlin denies backing the militias in order to exact revenge for the February 2014 ouster of a Moscow-backed president that was soon followed by Russia`s seizure of Crimea and the onset of one of Europe`s worst conflicts in decades.
Kiev`s Security Council said early Wednesday that the previous 24 hours had witnessed "some of the most intense bombardments of Ukrainian territory since the signing of the Minsk (truce) agreement" in February.
It said 16 servicemen had also been wounded but failed to specify where the most deadly exchanges of heavy weapons fire were being waged.
"The latest events are proof of yet another attempt by Russia and its puppet to wreck the Minsk agreement and restart active military hostilities," the Ukrainian Security Council said.
The insurgents said on their main website that the number of Ukrainian attacks had more than doubled to 85 from the 35 recorded Tuesday.The United Nations believes that more than 6,500 people have died and nearly 1.5 million been left homeless by a crisis that Ukrainian President Petro Poroshenko had vowed to resolve within days of being elected in May 2014.
But the Western-backed leader has instead seen the insurgents cement control over their holdings across the Russian-border regions of Lugansk and Donetsk.
Kiev and Washington accuse Russia of plotting periodic ground offensives that it backs up with tanks and rocket launchers as well as highly-trained military personnel.
Western reporters have also witnessed unmarked armoured vehicles crossing from Russia into the southeastern Ukrainian conflict zone.
But Moscow brushes off such charges as fabrications designed to discredit Russian President Vladimir Putin and distract from alleged Western meddling Ukraine.
Putin himself calls Russians fighting in Ukraine patriotic volunteers and off-duty soldiers who are following "the call of their heart".
Yet the veteran Russian leader and Poroshenko reluctantly put their names on a February truce deal that was personally promoted by Germany Chancellor Angela Merkel and French President Francoise Hollande.
Both European leaders are close Kiev allies who nonetheless value keeping lines of communication with Moscow open.
Merkel and Hollande argue the truce can be saved by Ukraine`s adoption of a constitutional amendment that spells out the eastern guerrilla`s right to control their regions for an interim period of three years.
The EU duo pressed that message on Poroshenko during a conference call on Friday and repeated it to Ukrainian parliament Volodymyr Groysman on Tuesday evening.
US Assistant Secretary of State Victoria Nuland will meet Groysman on Wednesday during a two-day visit that coincides with parliament`s vote Thursday on the changes to Ukraine`s basic law.
Nuland is also expected to meet Poroshenko and Prime Minister Arseniy Yatsenyuk, one of Kiev`s harshest critics of Moscow and a figure seen in Washington as vital to pushing Ukraine along its difficult economic restructuring path.
But some analysts share Yatsenyuk`s reluctance to give the rebels formal powers in the midst of a conflict that repeatedly flares and shows few signs of approaching a definitive end.
"Why does the West encourage Ukraine to proceed with decentralisation despite Russia`s obvious breach of Minsk?" analyst Maksym Khylko asked in a paper published by the US-based Atlantic Council policy institute.
Because "the Kremlin succeeded in intimidating the EU with threats of escalation to full-scale war," wrote Khylko.
"The West has not developed a clear plan if Minsk fails, and therefore it needs some evidence that the agreement is still alive," he added.