Two senior Russian military officers have been killed in eastern Ukraine, the Russian Defense Ministry said Sunday, the latest high-profile losses for Moscow in a grinding war with its western neighbor. The ministry said the two officers – Col. Vyacheslav Makarov and Col. Yevgeny Brovko – were in killed in action while leading Russian troops in the Donetsk region. It did not specify when or exactly where they were killed. "The commander of the 4th motorized rifle brigade, Colonel Vyacheslav Makarov, being at the forefront, personally led the battle," a Russian Defense Ministry briefing read. Brovko, the deputy commander of the army corps for military-political work, was leading troops in "repelling enemy attacks" and "heroically died after receiving multiple shrapnel wounds," the ministry said. The Donetsk region of Ukraine includes the city of Bakhmut, which has seen some of the fiercest and most relentless fighting of the war. A months-long assault on the city by Russian forces, including Wagner mercenaries, has driven thousands from their homes and left the area devastated. But despite the vast amounts of manpower Russia has poured into capturing the city, they have been unable to take total control, and in the past week suffered heavy losses in the area. Ukrainian forces have been able to capture more than 10 Russian positions near Bakhmut, Ukrainian Deputy Defense Minister Hanna Maliar said in a Telegram post on Sunday. Maliar called the situation in Bakhmut "very hot." The Ukrainian military reported on Sunday that Bakhmut and Maryinka in eastern Ukraine remain the "epicenter of fighting" "The enemy continues to focus its main efforts on the Lyman, Bakhmut, Avdiivka and Maryinka directions. In total, about 30 combat engagements took place in the above-mentioned areas over the last day," the military added. The Russian Defense Ministry said Ukraine has made "massive attempts to break through the defense of our troops to the north and south of Artemovsk," referring to Bakhmut by its Russian name. "All the attacks of the Armed Forces of Ukraine (AFU) have been repelled. There has been no breakthrough in the defense of Russian forces," the statement read. Also in eastern Ukraine, Russian targets in the occupied city of Luhansk have been hit in missiles strikes in the past several days. The city has become a significant hub for Russia's invasion effort and has rarely been hit by Ukrainian attacks since the war began. But two missiles hit in the area on Friday and another explosion was reported there on Saturday. Some Russian bloggers, without providing evidence, suggested Ukraine used cruise missiles recently provided by the United Kingdom. But Kyiv also has Ukrainian-made Grom missiles, which have the range to hit Luhansk. Elsewhere, unconfirmed reports said Russia may have had four military aircraft shot down over its own territory on Saturday, which if true would mark a significant coup for Ukraine. One Russian media outlet said that at least two combat aircraft – an Su-34 fighter/bomber and an Su-35 fighter – and two Mi-8 helicopters crashed. The aircraft were reportedly lost in the Russian region of Bryansk on the border with Ukraine. Multiple crashes within Russian territory at the same time would be unprecedented. Some analysts believe Ukrainian air defenses may have been pushed forward as the Russian air force uses more "glide munitions" that can fire at targets from distance. — CNN