As armored vehicles rumbled through downtown Kiev in an ostentatious celebration of Ukraine's independence, pro-Russian rebels who are battling government forces in the east paraded captured soldiers down the besieged streets of Donetsk and displayed charred wreckages of destroyed Ukrainian tanks.

Sunday's rival demonstrations on Ukraine's 23rd anniversary of independence from the Soviet Union underscored the bitter divide in a country already five months into warfare and making plans for potentially years more of tensions.

President Petro Poroshenko, addressing a highly militarized independence rally in Kiev, vowed to defeat the rebels and safeguard Ukraine's border with Russia by sharply raising defense spending for the coming three years. He warned that Ukraine too often in history had been caught by surprise from eastern invasions.

"It is clear that in the foreseeable future there will always, unfortunately, be the threat of war," Poroshenko said. "And we not only have to learn to live with that. We must always be prepared to defend our independence."

The rebels responded with their own show of strength in their stronghold of Donetsk, parading dozens of captured soldiers through the streets as bystanders tossed eggs and bottles at them. The insurgents also dumped battle-scarred Ukrainian military equipment on a central square, a bold rebuke to Kiev's announcement that it plans to strengthen its military.

While public support and mobilization for Kiev's campaign against the separatists is growing in much of the country, resentments fester in much of the east, where civilian casualties and shelling, often from Ukrainian military positions, have become a part of daily life.

In Kiev more than 20,000 people, many waving the country's blue and yellow flags or donning traditional embroidered shirts, watched the parade on Kiev's Independence Square, where months of protests earlier this year ended in the ouster of the country's former pro-Russian president.

Poroshenko announced he would raise military spending by 40 billion hryvnia ($3 billion) through 2017, an effective 50 percent increase from current budget targets.

Ukrainian military leaders have pleaded for extra resources as they face a potentially protracted fight against separatists. In recent weeks, Kiev's troops have scored heavy gains in territory and encircled the east's regional capitals of Luhansk and Donetsk. The United Nations estimates that more than 2,000 civilians have been killed in the fighting since April, a toll that rises almost daily.

Andriy Lysenko, spokesman for the Ukrainian National Security Council, told journalists Sunday that 722 members of Ukraine's armed forces have died in the fighting, with five killed and eight wounded in the past day alone.

In Donetsk, militants paraded captured soldiers, some dressed in military fatigues and others in tattered civilian clothes, through a central square as people in a crowd of several thousand shouted abusive slurs at them.

One visibly agitated man yelled obscenities as he held an infant in one arm. A woman shouted "Hang the fascists from a tree!" Other women rushed at the prisoners, trying to kick and slap them, and were restrained by rebel fighters.

The rebels placed several fire-blackened, shrapnel-shredded Ukrainian military vehicles in Donetsk's main square. Russian nationalist songs blasted from speakers as supporters posed for photos in front of a destroyed tank. The crowd appeared on edge as dozens of fighters gathered in formation, then quickly dispersed at the sound of artillery fire in the distance.

"Today is the so-called independence day of what was Ukraine. And look what has happened to their equipment. This is what has become of Ukraine!" said a pro-Russian rebel fighter who identified herself by her battle name, Nursa, pointing at the remains of a Ukrainian troop transport.

One onlooker grabbed a Ukrainian flag from the wreckage of one tank and threw it to the ground. Several others trampled on it, wiping their feet and spitting.

Alexander, a 40-year-old businessman from Donetsk who declined to give his surname, said the Ukrainian flag had no place in the city.

"I feel this is no place for this flag. The great achievement here is that people can see it in the state that it deserves to be in," he said.

Resentment has grown in the east as residential areas have increasingly come under fire. Early Sunday, artillery shells struck several residential buildings as well as a major hospital and morgue in downtown Donetsk, although nobody was reported killed.

In Kiev, Lysenko denied that Ukraine's forces were responsible for the shelling of any residential buildings or hospitals.

An estimated 300,000 of Donetsk's population of 1 million have fled the fighting, and many of those who remain have gone weeks without electricity or running water, and have spent recent days staked out in bomb shelters.

Conditions are worse in the city of Luhansk, whose war-reduced population of a quarter-million people has suffered under constant fighting over the past weeks.

Lysenko said 68 civilians had been wounded there in the past 24 hours, but could not confirm whether anyone had been killed.

In another symbolic move, Poroshenko traveled south to the predominantly Russian-speaking port city of Odessa to give a second speech on Sunday. Ukrainian television showed footage of navy ships bobbing by the shore on a stormy, turbulent sea. Ukraine lost much of its coastline when the Black Sea peninsula of Crimea was annexed by Russia in March, and the loyalty of local authorities in Odessa to Kiev has been a top priority for the new government.

Poroshenko and his Russian counterpart Vladimir Putin are set to meet Tuesday in Minsk, Belarus, alongside other European Union leaders. The two leaders have not met since early June, and many hope that the talks could help defuse the conflict in east Ukraine.

But German Chancellor Angela Merkel on Sunday cautioned against expectations of a decisive breakthrough at the much-anticipated meeting.

"The meeting in Minsk certainly won't yet bring the breakthrough," she said. "But you have to speak to one another if you want to find solutions."