Pro-Russian rebels in eastern Ukraine paraded dozens of captured soldiers before a jeering crowd on Sunday in mockery of Independence Day celebrations in the capital.
Ukraine's pro-Western government had sought to boost morale with an upbeat military parade to mark the country's independence from the Soviet Union in 1991.
Speaking to a crowd of thousands in the iconic Independence Square, known locally as the Maidan, President Petro Poroshenko decried Russian "aggression" and said he was "convinced that the battle for Ukraine, for independence, will be our success".
But it was a markedly different scene in the eastern rebel stronghold of Donetsk, where around 40 or 50 captured government soldiers were paraded through the city's central Lenin Square as onlookers hurled garbage and empty bottles at them.
"You are killing children!" screamed some in the crowd at the prisoners, who walked with heads bowed and their hands behind their backs before being placed on two buses and taken to an unknown destination.
The grim scene appeared designed to recall the famous moment in 1944 when thousands of captured Nazi soldiers were paraded through Moscow on Stalin's orders.
Human Rights Watch deputy director Rachel Denber said on Twitter that the event amounted to "humiliating and degrading treatment" of prisoners and was therefore in breach of the Geneva Convention.
- War in 'central Europe' -
Ukraine and the West blame Russia for supporting the separatist insurgents still clinging on to territory after four months of fighting in the restive east.
"War has come to us from over the horizon where it was never expected," Poroshenko told the crowd in the Maidan, many of whom sported the blue and yellow national colours and traditional dress as they celebrated the first military parade in five years.
He said some of the equipment rolling through the Maidan, which included tanks and Grad missile systems -- controversial for the indiscriminate damage they have caused in the east -- would be sent from the display straight back to the front lines, where over 700 soldiers have died since April.
"In the 21st century, in the centre of Europe, there is a flagrant attempt to breach the border of a sovereign state without declaring war," he said.
"It is as if the world has returned to the 1930s, the eve of World War II."
Poroshenko pledged 40 billion hryvnias ($3 billion, 2.3 billion euros) to its cash-strapped army over the next three years for the purchase of warplanes, warships and helicopters. He called it "only the modest beginning" of the rebirth of the Ukrainian military.
- Church shelled -
Kiev's conflict with the pro-Russian rebels in the separatist regions of Lugansk and Donetsk has claimed more than 2,200 lives since April. There is mounting concern over civilian casualties as the government presses closer into the rebel's last redoubts.
Ukrainian Orthodox Church said Sunday that an artillery attack the day before in the town of Kirovske in Donetsk region sent a shell through the roof of a church during a religious service, killing three people, while another shell killed two more in a local hospital.
In Donetsk, one of the largest hospitals was hit Sunday, sending patients and staff fleeing to the basement. Two people were killed in an evening attack south of the city centre, local authorities said.
Human rights organisations have said both sides of the conflict are guilty of using indiscriminate weapons and urged against locating military targets in urban areas.
The president of the self-declared pro-Russian People's Republic of Donetsk claimed French military "experts" were joining separatist forces battling government troops in eastern Ukraine.
"Tomorrow, we will receive officers from France. They are specialists ready to fight with us," Alexandre Zakhartchenko said at a Sunday press conference, without giving details.
- Pope calls for peace -
A number of Western leaders, including US President Barack Obama, congratulated Ukraine on Independence Day and Pope Francis extended a message of peace.
He called for prayers to Ukraine's "sons and daughters, to their aspirations of peace and tranquility, threatened by a situation of tension and conflict that continues unabated, causing so much suffering for the population”.
Ukraine's leader is under pressure to forge some form of agreement with Russia's President Vladimir Putin when they meet alongside EU officials in Minsk on Tuesday.
Germany's Angela Merkel, who met Poroshenko Saturday in Kiev, told ARD channel that she wants to "find a way that doesn't harm Russia" and stressed that "there won't be a military solution to this conflict".
Earlier this week Moscow set off alarm bells by driving in a convoy of more than 200 trucks in a unilateral aid mission to war-torn Lugansk, where people had been without power or communication for three weeks - a move slammed by Kiev as a "direct invasion".