Mr Medvedev warned Mr Trump against playing the time game with Russia.
Kirillov, a chief of Russia’s nuclear, biological, and chemical protection troops, was killed outside an apartment building along with his assistant.
He claimed that some veterans of elite Russian military units and foreign actors could have been involved in it.
The recapture of Lyman forced a close ally of Russian President Vladimir Putin to call for the possible use of low-grade nuclear weapons.
Russia is insinuating that it will use nuclear weapons against Kyiv if Ukraine attempts to retake annexed Ukrainian regions.
Lithuania said Russia’s threats were nothing new and that it had deployed nuclear weapons to Kaliningrad long before the war in Ukraine.
Russia added that in spite of sanctions it could fare well without what it cast as a deceitful and decadent West.
