UNITED NATIONS (UNITED STATES) - The United Nations on Friday urged all sides in Ukraine to fully uphold a Europe-brokered ceasefire, as the warring parties accused each other of jeopardizing the truce.
Ukraine has accused pro-Moscow rebels of going on the offensive, while separatist forces say they are merely defending themselves and the region's Russian speakers
UN political chief Jeffrey Feltman warned during an emergency Security Council meeting: "We are either looking at a return to a deepening intractable conflict or a momentary upsurge in parts of the conflict zone.
"We cannot afford either scenario."
The latest flareup in east Ukraine has left at least 28 dead and sparked fears that the escalation will derail the hard-won ceasefire brokered by France and Germany four months ago.
The Ukrainian military accused pro-Moscow rebels of targeting its positions around Donetsk on Friday, while separatists said Kiev's forces had used Grad rockets against them.
"The adversary is actively using 120-millimeter mortar launchers, 122-millimeter guns and tanks firing virtually without a pause at our positions," Ukrainian army spokesman Andriy Lysenko said in Kiev.
Lysenko said four Ukrainian soldiers had been wounded over the past 24 hours, while separatist commander Eduard Basurin told reporters one rebel had been killed and four wounded.
One child was killed and three adults were wounded during the shelling of the village of Telmanove late Thursday, Basurin added.
At the Security Council meeting in New York, the UN official declared: "The ceasefire must be fully respected and the protection of civilians a priority."
-Russia vs US-
At the United Nations, Russia and the United States traded barbs over who was responsible for the latest upsurge in fighting.
Russian Ambassador Vitaly Churkin accused Kiev's forces of targeting civilians in shelling attacks and of failing to fulfill its commitments to reach a political agreement.
"A critical moment has come," said Churkin.
"If we allow Kiev to continue to not implement the absolutely necessary political measures with regard to Donbass, the situation could fall out of control with unpredictable consequences," he warned.
US Ambassador Samantha Power shot back.
"The recent violence is rooted in a combined Russian-separatist assault," she said.
Amid growing alarm over the fate of recent peace gains in east Ukraine, Power is due to travel to Kiev next week to meet with Ukrainian politicians and get a first-hand account of the situation.
Fighting surged on Wednesday near the village of Maryinka, but clashes subsided in Thursday and Friday in the Donetsk region.
President Petro Poroshenko has warned of a full-blown Russian invasion in the east of the country, accusing Moscow of deploying more than 9,000 troops in support of the separatists.
The Kremlin has accused Kiev of seeking to torpedo the fragile truce ahead of an EU summit in June to discuss whether to extend sanctions against Russia that are to expire in July.
The United States, the EU and Germany all expressed alarm over the renewed violence, with Washington warning Russia it would face new punishment if the crisis escalates.
-G7 faces Ukraine crisis-
The Ukraine crisis will be high on the agenda of a G7 meeting that will be held in the Bavarian Alps without Russia this weekend.
Poroshenko said he would speak by phone with US President Barack Obama and German Chancellor Angela Merkel ahead of the gathering.
On Saturday, Poroshenko is also expected to meet with Japanese Prime Minister Shinzo Abe, who is to visit Kiev ahead of the G7 summit in a show of support.
NATO Secretary-General Jens Stoltenberg called on Russia to stop supporting separatists, while a French diplomatic source suggested that rebels were behind the escalation.
"Those who provoke it are interested in there being an exacerbation of the situation ahead of the G7," the source said.
The Ukrainian army has admitted it resorted to the use of heavy artillery banned by the European-brokered peace agreement but accuses the rebels of also using prohibited weapons.
Kiev and the West accuse Moscow of backing the Russian-speaking rebels with weapons, money and troops.
"The entire Russian military arsenal is already there, everything but submarines," Poroshenko said on Friday.
More than 6,400 people have been killed in the fighting since April 2014 and more than 1.3 million have been displaced.