Ukraine rebels vow to raise army of 100,000 troops to fight government forces

The US is reportedly considering providing military assistance to Ukraine

Pro-Russian rebels in Ukraine have vowed to muster another 10,000 men to boost their ranks to 100,000 as fighting continues.

Alexander Zakharchenko, leader of the self-proclaimed Donetsk People's Republic (DNR), claimed a “general mobilisation” would achieve the target but did not elaborate on details.

“A general mobilisation is planned in the DNR in 10 days. Ten thousand men will be called up,” the Russian RIA news agency quoted him saying.

“The joint army of the DNR and the LNR [Luhansk People's Republic] will be 100,000 men strong.

"Mobilisation is the first stage; there will be volunteers first and we will see what to do next."

Mr Zakharchenko, who was elected in a vote in November that was not recognised by the Ukrainian government or the West, did not say how many separatists were currently fighting.

The leader of the self-declared Donetsk People’s Republic Alexander Zakharchenko (on left) next to kneeling captive Ukrainian soldiers at a bus stop where 13 people were killed (AFP/Getty Images)

Critics have said it was unlikely that the rebels could mobilise such a high number of troops, suggesting the announcement could be a guise to bring in more Russian volunteers.

Kiev, Nato and Western governments have presented evidence they say proves Russia has sent troops and weapons to support the rebels but Moscow denies this. Ukrainian President Petro Poroshenko put the number of Russian troops in the east last month at 9,000.

Fighting has increased in eastern Ukraine in the past few weeks and hopes of easing the situation faded after peace talks collapsed yet again on Saturday.

Ukrainian forces have also mobilised more troops because of the surge in fighting, lessening further the hopes for a peaceful revolution in the near future.

A rebel comforts a wife of a killed civilian in shelling in Donetsk (AP)

The US could be on the brink of sending military assistance to Ukraine’s floundering military, a source in Washington has said.

The anonymous official claimed that Barack Obama continues to have concerns about the move, including the risks of starting a proxy war with Russia and the Ukrainian military's capacity for using US-supplied weaponry.

Russian Foreign Minister Sergei Lavrov accused the United States on Monday of supporting efforts to resolve the crisis in Ukraine with force after media reports that Washington is taking a new look at providing Kiev's forces with "lethal aid".

On hearing the reports, Russian foreign minister Sergey Lavrov said: “The rhetoric shows Washington's intention to continue doing everything possible to unconditionally support Ukraine's authorities who have apparently taken a course towards a military solution to the conflict.”

Prospects for a truce looked worse than ever after a new set of negotiations collapsed on Saturday in Minsk, Belarus, where the long-shattered peace treaty was drawn up between rebels and the government in September.

Dozens of civilians have been among those killed in recent days as shells rained on the rebel stronghold of Donetsk city and the besieged towns of Debaltseve and Vuhlehirsk.

Civilians in Debaltseve board an evacuation bus on Saturday (AP)

Debaltseve, a strategic railway hub, has been almost completely surrounded by rebel forces and the one road still open for families to escape has been targeted by artillery fire.

Ukraine's government said on Sunday that 13 of its troops were killed and another 20 wounded in a day of fighting across the region.

More than 5,100 people have so far been killed in the conflict and more than 900,000 have been displaced since it began in April, according to UN estimates.

Additional reporting by agencies