KIEV, Aug. 26 (Xinhua) -- Ukrainian authorities said Tuesday that Russian helicopters attacked a border post in Lugansk region in eastern Ukraine on Monday, killing four border guards.
"Two combat helicopters Mi-24 of Russian Armed Forces fired unguided rockets against Ukrainian border guards. The attack left four border guards dead and three wounded," Andrei Lysenko, spokesman for Ukraine's National Security and Defense Council, told reporters during a media briefing.
After the attack, a fierce fighting erupted on the Ukrainian-Russian frontier, Lysenko said, adding that government forces have managed to prevent "saboteurs" from crossing into Ukraine from Russia.
Lysenko also said that government forces have captured 10 "Russian soldiers" in the eastern Donetsk region, who crossed into Ukrainian territory on a "special mission".
On Monday, the Ukrainian State Security Service claimed to have seized servicemen from Russia's regular army and published a video footage on its Facebook page, depicting people dressed in military camouflage, who said they were Russian paratroopers.
Moscow has not commented on the case, while Russia's RIA Novosti news agency cited a source in the Russian Defense Ministry as saying that those captured servicemen were involved in patrolling the Russian-Ukrainian border area and "most likely crossed border by accident."
Kiev has long accused Moscow of supporting the independence-seeking insurgents in eastern Ukraine and fighting alongside them. Moscow has consistently rejected such accusations.