Ukraine has carried out a drone attack against targets in southern Russia, and claims to have destroyed six Russian planes at an airbase in Rostov region. Security sources told BBC Ukrainian eight more aircraft were badly damaged, and 20 service personnel could have been killed or injured. The Morozovsk base houses Su-27 and Su-34 aircraft used on the front line in Ukraine, the sources said. There has been no word from Russia on reports of an airfield attack. The BBC has been unable to independently verify the reports. However, Russian officials said that more than 40 drones had been aimed at the region, which borders Ukraine. The defence ministry said Saratov, Kursk, Belgorod and Krasnodar regions had also been targeted. It said all the drones were shot down. In Rostov"s Morozovsk district, an electrical substation was hit, leaving about 600 people without power for a few hours, Rostov Governor Vasily Golubev said on his Telegram channel. He added that there had been some damage to a 16-storey residential block. In a later post, he said eight people had been injured by explosives detonating on one of the fallen drones during an investigation of the site "not far from the aerodrome". Ukraine has stepped up drone attacks on targets within Russia recently, targeting military and energy facilities. It has warned repeatedly that its army is facing severe ammunition shortages, but has set a target of producing a million drones domestically this year. On Tuesday it claimed responsibility for a drone attack in Tatarstan, more than 1,300km (807 miles) from the Ukraine-Russia border. The strikes, targeting a drone factory and an oil refinery, are the deepest into Russian territory since the start of the war. Twelve people were reported injured. — BBC