Donetsk: Artillery fire rocked east Ukraine`s rebel stronghold of Donetsk on Sunday as separatists appeared to be reinforcing their frontline and fears grew of a return to all-out fighting.
The boom of shelling rumbled on mid-morning on the edge of Donetsk, where government forces regularly exchange heavy fire with insurgent fighters, but was less intense than overnight when mortar fire was heard close to the centre for around two hours, an AFP journalist reported.
It was the fiercest combat in the region since the September 5 signing of a frequently-violated ceasefire that halted full-scale confrontations across most of the conflict zone but failed to end constant bombardments at strategic hotspots.
An AFP crew saw a convoy of 20 military vehicles and 14 howitzer cannons without number plates or markings driving through the rebel town of Makiivka in the direction of the nearby frontline around Donetsk, where Ukrainian troops are struggling.
The Organisation for Security and Cooperation in Europe (OSCE) voiced concern Saturday after its monitors witnessed unmarked columns of tanks and troop carriers moving through east Ukraine in territory held by pro-Russia separatists.
The sightings of armoured columns came after Ukraine`s military said Friday a large convoy of tanks and other heavy weapons entered the country from Russia across a section of border that has fallen under the control of rebel fighters.
Russia denies being involved in the fighting in the east.
However, it openly gives the rebels political and humanitarian backing and it is not clear how the insurgents could themselves have access to so much sophisticated and well-maintained weaponry.
In March, Russian soldiers without identification markings took over the southern Ukrainian region of Crimea. Moscow annexed the peninsula shortly after.
The OSCE reports from the east came as fears mounted of a total breakdown in the two-month truce, with the war having already killed some 4,000 people, according to UN figures.
Ukraine`s military said Sunday that three servicemen were killed and thirteen injured as shelling hit government positions around the region.
That follows another bloody day Saturday when Kiev reported eight of its soldiers killed within 24 hours. Unidentified military columns have been seen increasingly by foreign journalists in the east in recent days, and Ukraine`s military on Sunday repeated allegations that Russia is covertly deploying troops to bolster rebels ahead of a fresh offensive.
The OSCE`s statement gives weight to concerns that the stuttering peace process could soon be ditched definitively.
"More than 40 trucks and tankers" were seen driving on a highway on the eastern outskirts of Makiivka, said the OSCE representatives, who are in Ukraine monitoring the ceasefire.
"Of these, 19 were large trucks -- Kamaz type, covered, and without markings or number plates -- each towing a 122mm howitzer and containing personnel in dark green uniforms without insignia. Fifteen were Kraz troop carriers," the report said.
Separately, the OSCE monitors said they had seen "a convoy of nine tanks moving west, also unmarked" just southwest of Donetsk.
The OSCE said all these forces were on territory controlled by the separatists` self-declared Donetsk People`s Republic.
The Swiss foreign minister and OSCE chairperson-in-office, Didier Burkhalter, said he was "very concerned about a resurgence of violence in the eastern regions of Ukraine", and urged all sides to act responsibly.The conflict has sent relations between Western backers of Ukraine and Russia to their lowest level in decades.
Russian President Vladimir Putin is gearing up for a fraught week of diplomacy with visits to the Asia-Pacific Economic Cooperation summit in Beijing and Group of 20 meeting in Brisbane, Australia, where he looks likely to face a hostile reception from Western leaders.
The last Soviet leader, Mikhail Gorbachev, said the world "is on the brink of a new Cold War" sparked by Ukraine.
"Some are even saying that it has already begun," Gorbachev said at an event Saturday marking the 25th anniversary of the fall of the Berlin Wall.
Russia`s economy is suffering from European Union and US sanctions imposed in response to Moscow`s support for the separatists.
With Russia welcoming last week`s rebel elections, which were billed as boosting the separatists` claim to independence, the sanctions look set to remain in place -- and possibly be reinforced.