Moscow (AFP) - Russia said Tuesday it had deployed jets and artillery to destroy an armed group that penetrated its border from Ukraine, while the Kremlin demanded the military prevent any repeat attack.
The armed incursion was the most serious since the beginning of Moscow's offensive in Ukraine last year, prompting the Kremlin to express "deep concern" and the evacuation of nine villages in the southern region of Belgorod.
The defence ministry's announcement that it used the air force and artillery on Russian territory represents an unprecedented use of force domestically since the military campaign in Ukraine began last year.Regional authorities said 12 civilians were wounded.
"In the course of the counter-terrorist operation, the nationalist formations were blocked and destroyed by air strikes and artillery fire," the Russian defence ministry said in a statement.
"The remaining (fighters) were driven back to the territory of Ukraine, where they continued to be hit by fire until they were completely eliminated," the ministry said.
The Kremlin voiced "deep concern" after explosive strikes had forced civilians from border villages to flee.
Local authorities said the Belgorod region had come under sustained artillery and mortar fire during fighting with a group it claimed had crossed from Ukraine.
Moscow said Russian forces killed more than 70 Ukrainian fighters and destroyed four armoured vehicles, but AFP was unable to independently verify those claims.
'Deep concern'
Belgorod's governor Vyacheslav Gladkov said civilians have been evacuated from nine border villages in the region, which has previously faced shelling attacks that have killed dozens of people since Moscow launched its offensive last year.
"What happened yesterday is a cause for deep concern and once again confirms that Ukrainian militants continue their activities against our country," Kremlin spokesman Dmitry Peskov said.
Members of the anti-Kremlin Freedom of Russia Legion have claimed responsibility for the incursion into Belgorod, while Kyiv denied involvement.
Ukrainian Deputy Defence Minister Ganna Malyar said: "We are not waging war on foreign territories."
In a video released by a Telegram channel claiming to represent the anti-Kremlin group, a camouflaged spokesman, surrounded by armed men in fatigues, said on Monday: "Russia will be free!" -- a slogan frequently used by Russian opposition activists.
Security operations were ongoing Tuesday in the border areas, said governor Gladkov.
Several drones struck houses and a government building overnight but no one was killed, said Belgorod's governor as Ukraine's leader visited the eastern front line.
Gladkov added on Tuesday that it was too soon for residents who fled to return and said that authorities would give the all-clear when it was safe.
'Guerrilla movement'
On Monday, Russia said its troops were battling a "sabotage" group that entered from Ukraine and introduced an "anti-terror regime" in the region of Belgorod, a first since the start of Moscow's campaign in Ukraine in February 2022.
Britain's Ministry of Defence noted that "Russia is facing an increasingly serious multi-domain security threat in its border regions, with losses of combat aircraft, improvised explosive device attacks on rail lines and now direct partisan action."
Ukrainian presidential advisor Mikhaylo Podolyak suggested that Russian "guerrilla groups" could be responsible.
"The only driving political force in a totalitarian country of tightened screws is always an armed guerrilla movement," he said on Monday.
The "anti-terror regime" gives special powers to security services and entails the enforcement of a number of restrictions and measures including beefed-up security and communications surveillance.
A similar regime was in place in Chechnya between 1999 and 2009, when Russian authorities battled insurgents during Moscow's second military campaign in the mountainous region.
The attack on Russia's region was reported ahead of a widely expected Ukrainian offensive, though President Volodymyr Zelensky has said his country is not yet ready.
Zelensky visits front
Russia has been reinforcing hundreds of kilometres of front line with tank barriers, trenches and troops.
Zelensky on Tuesday visited Ukrainian troops on the frontline in the eastern region of Donetsk, where Russian forces have concentrated their efforts to capture territory.
"Every day on the battlefield, Ukrainian marines prove that they are a powerful force that destroys the enemy, liberates Ukrainian land and performs the most difficult tasks in the most difficult conditions," Zelensky said.
"And we need more of this force.So, from today, we are significantly increasing the potential of the marines and creating a marine corps," Zelensky said.
Ukrainian troops held back Russian forces around Vugledar during Moscow's winter offensive that gave the Kremlin only limited gains in the battle-scarred Donetsk region.