Ukraine's defence ministry says another Russian general, Lt Gen Yakov Rezantsev, was killed in a strike near the southern city of Kherson.
Rezantsev was the commander of Russia's 49th combined army.
A western official said he was the seventh general to die in Ukraine, and the second lieutenant general - the highest rank officer reportedly killed.
It is thought that low morale among Russian troops has forced senior officers closer to the front line.
Ukrainian media reported that Rezantsev was killed at the Chornobaivka airbase near Kherson, which Russia is using as a command post and has been attacked by Ukraine's military several times.
Another lieutenant general, Andrei Mordvichev, was reportedly killed by a Ukrainian strike on the same base.
Kherson was the first Ukrainian city to be occupied by Russian forces, although there are reports that daily protests are held there against the Russian occupation.
Although Russia has confirmed the death of only one general, Kyiv and western officials believe up to seven have been killed in fighting since the war began.
However the death of Maj Gen Magomed Tushayev of the Chechen national guard has been disputed.
It is unusual for such senior Russian officers to be so close to the battlefield, and western officials believe that they have been forced to move towards the front lines to deal with low morale among Russian troops.
The unexpectedly strong Ukrainian resistance, poor Russian equipment and a high death toll amongst Russian troops are all thought to be contributing to the low morale.
Russian forces are believed to be relying in part on open communication systems, for example mobile phones and analogue radios, which are easy to intercept and could give away the locations of high-ranking officers.
A person inside Ukrainian President Volodymyr Zelensky's inner circle told the Wall Street Journal that Ukraine had a military intelligence team dedicated to targeting Russia's officer class.
On Friday, a western official reported that a Russian colonel had been deliberately run over and killed by his own men, as a result of the scale of losses taken by his brigade.
The killing of the commander of the 37th motor rifle brigade "gives an insight into some of the morale challenges that Russian forces are having", the official said.
So far, Vladimir Putin has only referred to the death of one general, thought to be Maj Gen Andrey Sukhovetsky, in a speech soon after the start of the war.
Russia says 1,351 soldiers have died since the war began in Ukraine, although Kyiv and western officials say the number is much higher.
Russia's lost generals
Lt Gen Yakov Rezantsev was reportedly killed by a Ukrainian strike on the Chornobaivka airbase near the city of Kherson.
He was promoted to lieutenant general last year, and was commander of the 49th combined army of Russia's southern military district.
He is said to have taken part in Russia's military operation in Syria.
Andrei Mordvichev was killed by a strike on the Chornobaivka airbase near Kherson, according to Ukrainian officials.
He was the commander of Russia's 8th combined army of the southern military district.
His death was reported on 18 March.
Maj Gen Oleg Mityaev reportedly died somewhere near the city of Mariupol, a city in south-east Ukraine which has seen some of the heaviest fighting so far.
The nationalist Azov regiment claims to have killed him.
He was a commander of the Russian army's 150th motorised rifle division, a relatively new unit formed in 2016, and based in the Rostov region close to the Ukrainian border.
Ukraine claims that the unit was created in order to take part in the conflict in separatist-controlled areas of eastern Ukraine, although Russia denies that its military was involved in fighting there.
Maj Gen Andrei Kolesnikov, of the 29th combined army, was killed in fighting on 11 March, according to official Ukrainian sources.
The circumstances of his death were not given.
After Kolesnikov became the third Russian general reportedly killed in Ukraine, one western official told the Press Association that the Russian army may be suffering from low morale, which is why high-ranking military officers are moving closer to the front line.
Maj Gen Vitaly Gerasimov, chief of staff of Russia's 41st combined army, was killed on 7 March outside the eastern city of Kharkiv, according to Ukraine's defence ministry.
Kharkiv, close to the Russian border, has come under sustained attack from Russian forces.
Ukraine's military released a recording of what it said was two Russian security service officials discussing Gerasimov's death, and complaining that their secure communication networks no longer worked in Ukraine.
Gerasimov was involved in the second Chechen war, the Russian military operation in Syria, and in the Russian annexation of Crimea in 2014.
Maj Gen Andrey Sukhovetsky, a deputy commander at the same unit as Gerasimov, was reportedly killed by a sniper on 3 March.
Like Gerasimov, Sukhovetsky was part of Russia's military operations in Crimea and in Syria.
Unlike the other generals, Sukhovetsky's death was reported in the Russian media and Russian President Vladimir Putin confirmed in a speech that a general had died in Ukraine.