Ukraine and Russian Leaders Meet, after Kiev Captures Moscow Troops

The presidents of Russia and Ukraine hold key talks Tuesday with little hopes for a breakthrough in resolving the raging conflict pitting Kiev against pro-Moscow separatist rebels.

Hours before the crunch talks, Kiev ratcheted up tensions by releasing footage purporting to show 10 Russian soldiers captured on its territory who a Moscow military source claimed had crossed into Ukraine "by accident."

Ukrainian President Petro Poroshenko and Russian leader Vladimir Putin arrived in Minsk for a meeting with top EU officials and the leaders of Kazakhstan and Belarus, in a bid to defuse tensions that some fear could trigger all-out war between Kiev and and its Soviet master Moscow.

U.S. National Security Adviser Susan Rice slammed Russia for "military incursions" into Ukraine using artillery, air defense systems, tanks and troops, that she said represented a "significant escalation" in the conflict.

"Repeated Russian incursions into Ukraine unacceptable. Dangerous and inflammatory," she wrote on Twitter.

Kiev's security service said paratroopers from Russia's 98th airborne division were captured about 50 kilometers (30 miles) southeast of the main rebel stronghold of Donetsk.

Ukrainian media on Tuesday aired footage purporting to show the captured Russian paratroopers confessing to entering Ukraine in armored convoys.

"We traveled here in columns not along the roads but across the fields," says one of the men who identifies himself as corporal Ivan Milchakov from the 331st parachute regiment based in central Russia.

"I didn't even see when we crossed the border."

Kiev has long accused Moscow of stoking the separatist insurgency raging in its east, but this is the first time Ukrainian authorities have claimed to have captured soldiers from Russia's regular army.

"Officially, they are at exercises in various corners of Russia. In reality, they are participating in military aggression against Ukraine", Defense Minister Valeriy Geletey said on his Facebook page.

Moscow has repeatedly denied any involvement in the rebellion in Ukraine and demands Kiev halt its punishing offensive.

A Russian defense ministry source described the captured soldiers Tuesday as having crossed into Ukraine "by accident".

The soldiers had been "taking part in patrolling a section of the Russian-Ukrainian border; they crossed it most likely by accident, on an unequipped, unmarked section", Russian news agencies quoted the source as saying.

On the ground there appeared no end in sight to the four months of conflict that has already claimed some 2,200 lives and has sent tensions between Russia and the West soaring to levels not seen since the end of the Cold War in 1991.

Ukraine's forces accused Russian troops of trying to open a "new front" after an armored convoy crossed onto government-held territory Monday in the south of Donetsk region.

An AFP journalist reported seeing smoke rising from the town of Novoazovsk close to the Russian border, where Ukraine's military said fighting was raging with pro-Russian rebels.

Local authorities in the main rebel bastion of Donetsk said three civilians were killed in shelling overnight as the army pummels insurgent fighters hunkered down there.

The Ukrainian military meanwhile said that 12 soldiers had been killed and 19 wounded in the past 24 hours.

Fighting has intensified in the run-up to the key talks in Minsk with the rebels appearing to launch a counteroffensive after losing swathes of territory to a push by government forces.

It was unclear whether Poroshenko and Putin would hold bilateral talks during the meeting in Minsk, the capital of Belarus.

The two met briefly in France at ceremonies to mark the 70th anniversary of the D-Day landings at the beginning of June.

Officials from the EU and Russian-led Customs Union were set to discuss the crisis as well as trade following the signing of key political and economic agreements by Ukraine's new pro-Western leaders with the European Union in June.

It was the refusal by former president Viktor Yanukovych to ink the EU deal last year, instead choosing to favor Moscow's economic bloc, that sparked the protests that eventually led to his ouster and set in motion a chain of events that has seen the Russian annexation of Crimea and the pro-Moscow insurgency in the east.

As Ukraine's political transition continues, Poroshenko on Monday announced long-awaited early parliamentary elections for October 26.

The Kremlin also ratcheted up the pressure by announcing plans to send another aid convoy into eastern Ukraine "this week".

Russia unilaterally sent about 230 lorries carrying what it claimed was 1,800 tonnes of humanitarian aid to the rebel-held city of Lugansk on Friday after accusing Kiev of intentionally delaying the mission. Kiev condemned the move as a "direct invasion".

Some 400,000 people have fled their homes since April in fighting that has left residents in some besieged rebel-held cities without water or power for weeks.