The so-called "Russian Freedom" Corps announced attacks that included the entry of troops into the Shibikino region of Russia's Belgorod province, while Moscow launched a series of air attacks with missiles launched from strategic bombers from the Caspian Sea.
The pro-Ukrainian corps said it carried out shelling operations on the outskirts of the city, and a number of militants entered between houses, stressing that it carries out joint attacks with the so-called "Russian volunteers" corps, and is engaged in battles with Russian forces.
The Freedom Corps called on locals not to leave the bomb shelters because of Russian artillery shelling coinciding with their offensive operations, they said.
The group said it captured two Russian soldiers during the fighting in Belgorod and offered an exchange deal during a meeting with the region's governor.
Belgorod Governor Vyacheslav Gladkov accused Ukrainian forces of bombing a shopping area in Shibekino, 7 kilometers from the Ukrainian border, without causing casualties, and said that Russian air defenses intercepted air targets in the sky of the city.
Gladkov said the shelling had caused fires near the city's market, a special area and a grain warehouse, and wrote on Telegram "Emergency services at the site."
Belgorod province has been targeted since the first month of Russia's war on Ukraine, and the frequency and quality of attacks has increased in recent weeks, and the province is a major supply line for Russian forces inside Ukraine.
For its part, the Russian Wagner Group threatened an urgent intervention in the Belgorod province to settle what it called the "state of chaos" there, and Yevgeny Prigozhin, commander of "Wagner", said that his forces will intervene to protect the population in the Belgorod province if the Ministry of Defense does not settle what he called the "state of chaos" there soon.
Prigozhin stressed in an audio recording that his forces would not wait for permission from anyone to contain what he called the seizure of Russian territory.
Wagner withdrew days ago from the city of Bachmut and handed them over to Russian forces after taking control of them after months of fierce battles with Ukrainian forces.
In the Ukrainian capital Kiev, military officials said Russia had launched a series of air strikes with missiles fired from strategic bombers from the Caspian Sea, and that Ukrainian air defense systems repelled drones as they approached the capital.
The head of the city's military administration, Sergei Popko, said on Telegram early on Sunday: "According to preliminary information, no air target has reached the capital. "The air defenses destroyed everything that was actually heading towards the city before it arrived."
The military administration in Kiev said Russia attacked the Kiev region at dawn with rockets fired from the Caspian Sea and suicide bombers.
Kiev also announced that Russian missiles hit an airport near the city of Krupevnitski (central Ukraine), and Ukrainian Air Force spokesman Yuri Ignat told a television channel that Russian forces had fired "6 missiles and 5 attack drones."
"Unfortunately, not all of it was destroyed. Of the 6, 4 were destroyed by the air force, while two hit the airfield near Kropevnitzky," he said, without providing further details.
In Dnipro, Ukrainian authorities said a Russian aerial bombardment of the town of Podgoro Deninskaya hit a residential building, injuring at least 20 people.
In Crimea, pro-Russian authorities on the peninsula Moscow annexed from Ukraine in 2014 announced the downing of Ukrainian drones that were launching attacks on towns on the peninsula overnight, causing material damage.
The pro-Russian governor of Crimea, Sergei Aksyonov, announced the downing of 9 Ukrainian drones in Djankoy, adding that air defenses shot down 5 Ukrainian drones, and electronic warfare means controlled 4 other drones, noting that 3 houses and two cars were damaged in Djankoy as a result of the crash of one of the drones.
A senior Ukrainian government official on Sunday expressed surprise and "disbelief" when he learned that nearly half of the bomb shelters inspected during an initial inspection in Kiev were either closed or unusable.
Ukrainian President Volodymyr Zelenskiy ordered all Ukrainian shelters to be inspected on Friday, a day after a child, mother and another woman were killed in Kiev after they were unable to enter a shelter during a Russian air strike.
Ukraine's Minister of Strategic Industries Oleksandr Kamyshin said that of the 1078,359 shelters inspected by authorities on the first day, 122 were found to be unequipped, 597 were closed and <> were found to be usable.
"I received with a degree of disbelief the fact that (only) half of them were open and ready," he wrote on Telegram, adding: "Yesterday, when we inspected selected shelters in the Opulón district with the governor of the region, the absolute majority of shelters were closed."
Kamischin said the shelters would continue to be inspected. These inspections are taking place in the shadow of Russia's 17-month full-scale invasion of Ukraine.