Ukraine: Battles raging in heart of rebel-held Lugansk

Ukraine said Tuesday that fighting had erupted in the heart of the major rebel stronghold of Lugansk as government forces press a punishing offensive to win back the war-torn east.
Kiev's military claimed street battles with insurgents were raging in the city centre after one outlying district was "liberated".
If confirmed, any advance by Ukraine's army into Lugansk, which has endured brutal shelling and weeks without running water or electricity, would be a major breakthrough for Kiev after four months of fighting that has claimed over 2,100 lives.
Government forces also said they had recovered the bodies of 15 civilians burned alive when a convoy evacuating them from Lugansk was hit by a rebel missile strike on Monday.
A military spokesman had previously said that dozens of people were killed in the alleged attack.
The pro-Kremlin rebels have denied the allegations, which could not be independently verified.
But the claim of a strike on civilians drew calls for restraint from the United Nations and Washington, after weekend talks between Russian and Ukrainian foreign ministers failed to make any breakthrough.
UN Secretary General Ban Ki-moon said the "tragic incident makes the urgency of a ceasefire and a diplomatic solution even more stark".
Ban urged both Kiev forces and rebels to "allow safe passage to anyone attempting to leave areas of active military operations," a spokesman said.
The State Department in Washington said it had been unable to confirm who was behind the attack on the convoy and urged "all sides (to) take every precaution to protect innocent lives".
- No peace, no water -
Across the region, deadly shelling also rained down around the main rebel stronghold of Donetsk as government troops tightened the vice on rebels hunkered down in the city.
An AFP photographer in the adjoining city of Makiyivka saw the bodies of one woman and two men killed by shelling sprawled in the streets.
Smoke could also be seen billowing from the nearby town of Yasynuvata, where Kiev said its troops were conducting a "mopping-up" operation.
Residents in Donetsk, which had a pre-war population of one million, were also queueing again for water after fighting cut supplies over the weekend.
President Petro Poroshenko said on Monday that Ukraine was readjusting its military strategy following fresh rebel claims they were receiving troop reinforcements from neighbouring Russia to prop up their struggling insurgency.
Poroshenko said government forces were "regrouping" as they sought to continue the offensive.
More than 285,000 people have been forced to flee the fighting in industrial eastern Ukraine since insurgents took up arms against Kiev's rule in April.
Two senior UN officials -- Under-Secretary General Jeffrey Feltman and humanitarian aid chief Valerie Amos -- are set to travel to Kiev later this week.
Kiev said it was also looking forward to a "very interesting visit" by German Chancellor Angela Merkel Saturday, on the eve of Ukraine Independence Day.
Diplomatic efforts to defuse the conflict continued despite a crisis meeting between the foreign ministers of Ukraine, Russia, Germany and France on Sunday having broken up without any agreement on how to end the violence.
Ukraine's Foreign Minister Pavlo Klimkin lashed out at Russia for refusing "to recognise the facts" of the continuing flow of weapons and mercenaries across its border.
Russia has consistently denied Western allegations that it is funnelling weapons to the rebels and has called on Kiev's forces to halt their firing.
- Aid delayed -
A controversial Russian aid convoy was meanwhile still stuck waiting to be checked near Ukraine's restive border as haggling over whether it could cross dragged on.
Red Cross representative Laurent Corbaz headed to Moscow Tuesday to discuss with Russian officials the delivery of humanitarian aid to east Ukraine.
The Red Cross -- which is meant to oversee the delivery of the cargo -- says it has not yet received security guarantees on how it will cross rebel territory.
"We have no date, no hour" for when the convoy may go to the Ukrainian side, Paul Picard, a monitor for the Organisation for Security and Cooperation in Europe (OSCE) at the border, told journalists.
Kiev and the West fear the shipment is a ploy to bolster the rebellion or provide a pretext for Russia to invade, allegations dismissed by Moscow.