Russia said on Monday that its forces destroyed two Ukrainian combat vehicles that violated the Russian state border on Monday.
At about 6 a.m. Moscow time (0300 GMT) in the border area of Russia's Rostov region, Federal Security Service (FSB) officers discovered the penetration of a sabotage and reconnaissance group from Ukraine, the Russian Defense Ministry said.
To detain the intruders, the FSB border detachment requested reinforcements from the Southern Military District of the Russian armed forces, it said in a statement.
During the clash, two infantry fighting vehicles of the "Ukrainian Armed Forces entered Russia" to urgently evacuate the sabotage and reconnaissance group, said the statement.
A unit of the Russian armed forces promptly arrived at the scene of the clash and destroyed "both Ukrainian vehicles" by using anti-tank weapons, said the statement.
Five members of the sabotage and reconnaissance group were killed, while there was no casualty among the Russian troops and the FSB officers, it said.
Rejecting the allegation, Ukrainian Foreign Minister Dmytro Kuleba tweeted that "Ukraine did NOT send saboteurs or APCs (armored personnel carriers) over the Russian border, shell Russian territory" or "shell Russian border crossing."