Russia is still fighting for full control of the eastern Ukrainian region of Lugansk.
Its troops and artillery have so far failed to dislodge the Ukrainian defenders, who are clinging to the last bastion of the besieged city of Severodonetsk.
The governor of Luhansk said Russian forces were entering nearby areas and shelling Lysychansk, a town opposite Severodonetsk.
Meanwhile, Moscow says it retaliated after the attack on several Russian-controlled oil and gas facilities in the Black Sea.
The Russian Defense Ministry said it launched missiles at a Ukrainian airfield in the Odessa region and destroyed a hangar that housed drones.
Russian President Vladimir Putin was in the Kremlin on Tuesday as the fighting raged. He attended a graduation ceremony for future defense and intelligence officials.
Putin said: “Remember that the effective use of the theoretical knowledge you have acquired during training is possible only after receiving practical experience.”
The president also revealed during the ceremony that Russia is preparing to deploy state-of-the-art military equipment. He said new ICBMs and surface-to-air missile systems will be in use by the end of the year.
On Tuesday, US Attorney General Merrick Garland became one of the latest senior Western officials to visit Ukraine amid ongoing hostilities.
Garland met with her Ukrainian counterpart, Attorney General Iryna Venedictova.
The Attorney General said, “The United States sends an unequivocal message. There is no place to hide. We and our partners will pursue every means available to ensure that those responsible for these atrocities are held accountable.
Garland said the United States has established a special team to support Ukraine as it collects and analyzes evidence of war crimes committed by Russian troops.