Moscow, May 25 : Russia will respond quickly and extremely harshly to future incursions, Russian Defence Minister Sergei Shoigu said at a meeting with senior defence officials. The Minister on Wednesday mentioned that "a Ukrainian nationalist formation" that broke into Russia's Belgorod region on Monday was defeated. "Russia will keep responding to such actions of Ukrainian militants promptly and harshly," Shoigu said. The Russian Defence Ministry said on Tuesday that "more than 70 Ukrainian nationalists were killed during a counter-terrorist operation," and Russian forces were able to push the "remaining nationalists" back into Ukraine, where they were further eliminated. Kremlin spokesman Dmitry Peskov said on Tuesday that Russia was "deeply concerned" about the incursion, Xinhua news agency reported. Ukraine has said that the incursion was carried out by two anti-government paramilitary groups in Russia, adding that it was not responsible for the incident. Belgorod governor Vyacheslav Gladkov said on Wednesday that there had been a large number of drone attacks on the region overnight, adding that most of them were repelled. In a Telegram post, Gladkov added that the attacks damaged residential and administrative buildings, and that no casualties were reported. /IANS