MINSK (AFP) - Ukranian and rebel envoys concluded "difficult" marathon talks on Wednesday without agreeing the date of a new round aimed at ending the pro-Russian uprising devastating the former Soviet state's industrial east.
The five-hour preliminary discussion in the Belarussian capital Minsk had been tentatively due to be followed by a second meeting on Friday at which a final accord was to be signed.
But rebel representatives stressed that they could not yet promise whether the negotiations would resume as planned.
"We had a difficult preliminary meeting," Donetsk separatist region mediator Denis Pushilin told a pro-rebel news site.
"The date and time of the next meeting is still up in the air. It is under discussion," Pushilin said.
The self-declared Donetsk leader Alexander Zakharchenko later added vaguely that "a second round is still ahead."
Neither Ukrainian officials nor the Russian and European envoys spoke to reporters waiting outside the gated Belarussian state mansion that hosted the talks.
Sharply contrasting visions of Ukraine's place in Europe and its system of government have been persistently blocking a solution to the eight-month-old war.
The two Russian-border provinces of Lugansk and Donetsk rose up against the historic shift toward Europe that Kiev made in the wake of last winter's ouster of an unpopular Moscow-backed president.
The separatist commanders have since declared their own republics and will settle for no less than Ukraine becoming a loose federation in which they manage most of their own affairs.
This option is backed firmly by Russia but rejected by Ukrainian nationalists who make up an important part of President Petro Poroshenko's government.
Ukraine has remained tightly centralised since independence and is only now considering easing its hold over the country's regions in order to stem public resentment over the relative prosperity enjoyed in Kiev.
Such problems helped undermine two deals reached in Minsk in September that Poroshenko was forced into following a surprise rebel counteroffensive that Nato believes was backed by crack Russian forces and tanks.
Russian President Vladimir Putin flatly calls soldiers who crossed into the Ukrainian war zone volunteers who are "answering the call of the heart".
A UN count puts the number of deaths following an initial Sept 5 truce deal at more than 1,300.
The overall toll since last winter from Europe's bloodiest conflict since the 1990s is more than 4,700 and has caused friction between many of the country's Ukrainian and Russian speakers that may take generations to heal.
MONEY AT STAKE
The most important immediate issue for the rebels will be to make sure that Kiev resumes the social payments it suspended last month out of fear that they were being used to fund the revolt.
Russia's Kiev ambassador Mikhail Zurabov - Moscow's envoy at the talks who defends the insurgents' stance - said "economic" issues were one of the four main points on the agenda.
But a Kiev-based OSCE negotiator said the sides planned to steer clear of the payments debate.
The OSCE's Heidi Tagliavini added that also up for debate were the details of a mutual troop withdrawal and a prisoner swap.
Both Kiev and Moscow tried to talk up the prospects of a breakthrough being reached this week.
Poroshenko's top foreign policy adviser said the very fact that the sides had managed to arrange such a meeting was a promising sign.
"The work begins today, and by some point around Friday we should be able to achieve concrete results," Valeriy Chaly told reporters in Kiev.
And Russia's Deputy Foreign Minister Konstantin Dolgov said the consultations presented a "real chance" for peace.
UKRAINE LOOKS TO NATO
Adding to the tensions was the Ukrainian parliament's decision on Tuesday to officially drop the neutrality the country adopted under Russian pressure in 2010.
The ceremonial shift in Kiev's diplomatic allegiance was in line with Poroshenko's vow to put Ukraine under Western military protection in the face of Russian threats.
Ukraine sought Nato membership in the early post-Soviet era but, with its once-mighty army in ruins and riven by corruption, it was never viewed as a serious candidate.
The February change of regime in Kiev upset Putin's plans to get Ukraine to join a new bloc that Moscow hopes will counterbalance Nato and the European Union.
Moscow had also set Kiev's exclusion from all military unions as a condition for any Minsk deal.
Russia's defence ministry warned on Wednesday that Nato would break off all contacts with Nato should Ukraine ever become part of the Cold War-era bloc.