Russian military forces are gaining ground in eastern Ukraine. They have been targeting ports and railroads and other key infrastructure. And they have now seized a strategic railway hub.

Ukrainian officials confirmed that the city of Lyman is under Russian control. It is the second midsize city in the Donbas region to change hands this week.

Ukrainian forces say they are engaged in a "fierce defense" of a third city. They released footage of what they say is a strike on Russian troops outside of Severodonetsk. The city is Ukraine's last stronghold in the region.

The governor says Russians have encircled two-thirds of the city and destroyed 90 percent of the buildings. He says the shelling continues. Authorities believe that about 15,000 people have fled their homes to seek shelter.

One woman at an underground shelter said many people in there have a fever, and there's not much medicine. Everyone is sick.

Authorities at the UN say more and more civilians are being caught in the fighting. They say at least 4,000 of them have died but that the true number is likely much higher.

Ukrainian president Volodymyr Zelenskyy is looking for ways to stop the carnage. He has once again offered to sit down for talks with Russian President Vladimir Putin.

Zelenskyy said there are things to discuss with the Russian leader. He said he is not saying that he or his people have a desire to talk to him. He emphasized that there is not much eagerness, but they have to face the realities in which they live.

Peace talks have been stalled for weeks. Putin has put the blame on Ukrainian leaders. He says they are sabotaging the negotiating process.