Ukrainian President Petro Poroshenko on Saturday welcomed home as heroes 145 soldiers freed by pro-Russian rebels during the largest prisoner swap of the eight-month separatist war.

The Western-backed leader, beaming and wearing a black bomber jacket, walked up to the back cargo bay of a military transport plane that landed at a military airport outside Kiev in the dawn hours of Saturday to hail the men.

He firmly shook hands and tightly embraced them — some young and others sporting greying beards — as they trundled down the steps wearing regular civilian clothes and knitted scull caps in the searing cold.

“My heart as that of a president and citizen is brimming with joy that you — as I had promised — will be able to meet the New Year with your families and comrades and arms,” Poroshenko said as the released men huddled around him on the tarmac.

Ukraine’s chronically underfunded army has been criticised heavily by the public for failing to stamp out a revolt that has claimed 4,700 lives and continues to threaten the former Soviet republic’s very existence.

Poroshenko appeared to be addressing that rebuke by praising the men for “not breaking or changing and firmly keeping your military morale, demonstrating the best qualities of a Ukranian warrior”.

Ukraine’s allies in Europe hope that Friday’s exchange will mark a watershed moment in a war that seems at a stalemate but still rages on because of the immense mistrust between the two sides.

Kiev on Friday freed 222 insurgent fighters captured around the main rebel stronghold of Donetsk and its surrounding regions.

But the original deal — agreed with the help of European and Russian mediators in the Belarussian capital Minsk on Wednesday — called for the release of 150 state troops and 225 militants.

“Unfortunately, not everyone was released. Another four of your comrades will come back on (Saturday),” Poroshenko said in reference to a much smaller prisoner swap expected to take place in another part of eastern Ukraine.

“But we will search for and find everyone and not leave anyone behind,” Poroshenko promised.

“The country will fight for each one of its faithful sons.”

Saturday’s swap was due to involve both sides’ fighters captured in Donetsk’s neighbouring breakaway region of Lugansk.

– Stalled peace talks –

The Minsk negotiations were called to reinforce a largely ignored peace plan struck in September that aimed to both stem the bloodshed and ease the crisis in East-West relations the conflict has sparked.