Counterterrorism efforts have been announced in Kursk Region, Russia and two neighboring regions in response to a Ukrainian incursion, the National Antiterrorism Committee (NAC) announced late Friday.

Ukraine launched an attack against Kursk Region on Tuesday – its largest attack on Russian territory since the beginning of the conflict between the neighboring states.

The Kremlin called it a large-scale provocation and accused Ukrainian troops of indiscriminate attacks on civilians. Kiev has said one of the objectives of the incursion is to terrorize the Russian population and weaken their support for the government.

“The Kiev regime has launched an unprecedented attempt to destabilize the situation in a number of regions of our country,” the NAC’s information service said in a statement on Friday. “The terrorist attack” on Kursk “resulted in civilian casualties and the destruction of homes and other civilian facilities,” it added.

“In order to ensure the safety of citizens and suppress threats of terrorist acts by enemy sabotage and reconnaissance teams,” Federal Security Service (FSB) Director Aleksandr Bortnikov, who is also the NAC chairman, has made the decision to carry out counterterrorism operations in Belgorod, Bryansk, and Kursk Regions, the statement said.

Forces conducting counterterrorism efforts have the right to stop and search, enter properties, and limit the movement of people during the operation, according to a 2006 law. Communications systems are under strict control, and the sale of arms and alcohol is prohibited during the ongoing efforts, among other things.

Ukrainian forces in Kursk Region have lost at least 945 service members dead or wounded, as well as 102 pieces of heavy equipment, the Russian Defense Ministry said on Friday. Among the heavy equipment, Kiev lost 12 tanks, 17 armored personnel carriers, six armored infantry fighting vehicles, two anti-aircraft units, and three field artillery guns, it added.

Russian President Vladimir Putin called the attack a “massive provocation,” accusing Ukrainian troops of “indiscriminately firing various types of weapons, including missiles, at civilian facilities, residential buildings, and ambulances.”

According to Kursk Region interim Governor Aleksey Smirnov, the Ukrainian army has been actively attempting to impede civilian evacuation efforts, “firing at civilians and ambulances.” Some doctors have been killed, he reported to the president on Thursday.