Planned peace talks between Ukraine and pro-Russian rebels were postponed on Tuesday but a ceasefire appeared to be largely holding along the frontline in the ex-Soviet republic's war-shattered east.

The Ukrainian foreign ministry said negotiations with the insurgents involving Russian and European envoys in the Belarussian capital Minsk had been delayed and would probably not be held until Friday.

"Today, nothing will happen. Consultations are continuing," a foreign ministry spokesman told AFP.

But a ceasefire along the frontline in eastern Ukraine was apparently being respected on Tuesday on what the government has dubbed "a day of silence".

AFP reporters said fighting in the main rebel-held city of Donetsk had stopped abruptly at dawn after a night of artillery exchanges.

"We don't have any killed soldiers" since the start of the truce, a visibly emotional Ukranian President Petro Poroshenko told a public lecture in Singapore, where he was starting a brief Asian trip.

One rebel fighter stationed near the contested airport on the northern outskirts of Donetsk confirmed that the situation was "calm for the moment".

But his colleagues remained sceptical about the long-term prospects.

"I don't believe in the ceasefire," one told AFP, refusing to give his name. "Up to now, ceasefires have only meant a pause before even fiercer fighting resumes."

A fighter with the Ukrainian ultranationalist Pravy Sektor (Right Sector) group, stationed two kilometres from the airport, denied that shelling had completely stopped.

"There has been howitzer and mortar fire on Pisky," he told AFP by phone, referring to the village that serves as a base for government forces near the airport.

- Talks delayed -

Donetsk separatist negotiator Denis Pushilin told AFP that rebel leaders may hold a video conference with the Ukraine government and European observers about the agenda and venue for talks.

"Most probably we will be able to agree a date on Wednesday," Pushilin said. He had previously said Friday was the most likely date.

The pro-Western Ukrainian leadership is hoping to wind down the war so it can focus on long-delayed economic reforms meant to dig the country out of effective bankruptcy and open the way for more foreign aid.

A team from the International Monetary Fund (IMF) arrived in Kiev on Tuesday to assess Ukraine's implementation of deeply unpopular austerity measures it has demanded in return for $17 billion in emergency aid.

While observers waited to see if the ceasefire holds, fighting continued right up to the last moment with the government reporting the deaths of six soldiers on Monday.

The Minsk negotiations are supposed to reinforce an earlier peace deal reached in the same city on September 5 that failed to halt the fighting.

The United Nations says another 1,000 lives have been lost since.

UN estimates put the total death toll from the eight-month conflict at more than 4,300. But the number of rebels killed has never been firmly established and some believe the true numbers are much higher.

- Russia changing tack? -

Russia has faced an unprecedented level of criticism from the West over its support for the rebels in eastern Ukraine.

Even Germany -- usually one of the more doveish voices on Russia -- says the increasingly isolated Kremlin is trying to destabilise eastern Europe and prevent countries in the region from moving closer to the EU.

Russia has retaliated against harsh Western economic sanctions by banning Western food imports, among other restrictions, but analysts say Moscow has been caught off-guard.

The Kremlin has reportedly reshuffled its Ukraine policy team in recent weeks -- a possible sign it plans to change tack.

"Russia didn't expect such a profound change in attitude from Europe and especially Germany," said Kadri Liik, an analyst at the European Council on Foreign Affairs in Brussels.

It is "slowly starting to realise that things haven't worked out as hoped. The question now is whether Europe, and Germany in particular, can succeed in making Russia accept a face-saving way out."

German Chancellor Angela Merkel said Tuesday she was convinced the standoff could be resolved diplomatically, but "we will need staying power."