In a rare announcement of its losses on the battlefield, the Russian Defence Ministry said the commander of the 4th Motorised Rifle Brigade, Vyacheslav Makarov, and deputy commander of the Army Corps, Yevgeny Brovko, died in fighting in eastern Ukraine.
The news came as the battle for control of Bakhmut in the eastern region of Donetsk continued.
Col Makarov was killed as his brigade repelled attacks by Ukrainian troops south of the settlement of Krasne, a ministry statement said.
"Two attacks of the enemy had been repelled," it said. "As a third was being repelled, the brigade commander was seriously wounded and died during the evacuation from the battlefield."
Col Brovko was killed as Russian troops defended attacks elsewhere, the ministry said, saying he "died heroically, having received multiple shrapnel wounds".
Referring to the mercenary group Wagner, Moscow said "assault detachments" had continued to fight for control of western parts of Bakhmut with the support of airborne forces.
"Over the past day, the enemy has made massive attempts to break through the defence of our troops to the north and south of Artemovsk," the ministry said, referring to Bakhmut by its Russian name.
"All attacks of the Ukrainian armed forces have been repelled."
Wagner's chief Yevgeny Prigozhin has again accused the Russian army of inaction around Bakhmut.
In a post published by his press service, he disputed the ministry's claim that Russia's "airborne forces" had backed up his men.
"I didn't see them ... I don't know where they are and who they are helping," he said.
Defence Minister Sergei Shoigu last year said 5,937 Russian troops had been killed in the pro-western country, even though military analysts say Moscow has sought to hide the scale of its losses.
Ukraine and Russia have been wrestling for control of the city of Bakhmut for months.
Moscow on Friday acknowledged its forces had fallen back in the north of the city amid a surge of Ukrainian attacks, but Kyiv has played down suggestions that a huge, long-planned counteroffensive has officially begun.
Meanwhile, Ukraine's air force said it intercepted and destroyed three missiles and 25 drones overnight in the latest aerial attack.
Russia has increased the number of its missile and drone attacks this month, which Kyiv attributes to Moscow's fear of the expected Ukrainian counteroffensive.
Russia "attacked Ukraine from different directions with Shahed attack drones, Kalibr missiles from ships in the Black Sea, [and] cruise missiles from Tu-95 strategic aircraft", the air force said in a statement.
At least two people were injured in the western region of Ternopil, a senior Ukrainian presidential official said on the Telegram messaging app.
Ukrainian authorities do not report hits on critical or military infrastructure.