Zaporizhzhia, Ukraine(CNN) As the evacuation train rolled slowly into the main railroad station in the southeastern Ukrainian city of Zaporizhzhia on Saturday, panic began to rise among the hundreds of families desperate to claim a few of the limited spaces on board the service to Lviv, in the west of the country.
Most of those on the platform were women and children who had waited outside for hours in falling snow and freezing temperatures, trying to position themselves at the spot where the train doors might eventually open.
As the train ground to a halt, emotions spilled over, with women saying tearful goodbyes to their husbands and male relatives -- who are banned from leaving the country if aged between 18-60 -- while trying to get their children and belongings on board through the throngs of people.
The exodus from the city and from across Ukraine has been underway since Russia launched its invasion on February 24, with more than a million refugees pouring into neighboring countries. The pace of evacuations from Zaporizhzhia has escalated since Thursday evening, when the nearby nuclear power station in Enerhodar was captured by Russian soldiers, who set fire to a training building adjacent to the plant. Some residents fear the Russians will attack the city itself next, or try to impose power blackouts.
The takeover of the power station was the final push for 19-year-old Hanna Iliushchenko and her family to flee the country. They plan to head for Lithuania where they have friends.
"The situation is escalating," Iliushchenko said. "My mother and sister decided to leave, so that's why I'm leaving with them."
But Iliushchenko said it's "hard" for her to leave her boyfriend, 33-year-old Serhii Prytulo. The couple stood hugging and kissing on the edge of the platform of Zaporizhzhia 1 station as they said their goodbyes.
"I'm feeling bad. My country (is at) war," Prytulo said. "It's very bad for all the people." But he will stay behind to defend his birthplace, he added.
For families with children, their focus is on getting them to safety, either to western Ukraine or out of the country.
Oleg Khodarev cradles his two-year-old daughter Vassilisa in his arms and hugs his wife, as he prepares to separate from them with no indication of when they'll be reunited.
"We just want to save the life of the child," Khodarev said. "We could never imagine this."
Their family home is in central Zaporizhzhia near a civilian administration building. They fear that if the city were targeted, they would be in the line of fire.
"There are no proper bomb shelters," his wife, Natalia, said. "There are only a few basements in houses, but in those you can be easily trapped under ruins."
For others, leaving the city involved tough choices about those they had to leave behind.
Aleysa Panaseyko, 41, said she made the "hard decision" to travel alone to Lviv, because the 620-mile journey would be too difficult for her parents.
"They can't go because (they're) old people," Panaseyko said. "This situation (is) very sad."
Many elderly people have decided to stay in Ukraine, either because they don't want to leave their homes, or because they aren't strong enough to make the trip -- or because they want to help the war effort.
80-year-old Mykola Tymchishin stood on the platform behind the jostling crowd, hoping to see his daughter and grandson make it onto the train.
Although he could leave, he tells CNN he is "staying to fight" as he "might be of some use here."
"I made Molotov cocktails," he said. "I have great rifles. I'm a hunter with 40 years of experience. I'm staying."
An ex-paratrooper from the airborne assault battalion in the Soviet army, he shows off a star-shaped medal that he carries around in his coat pocket.
He "hates" the invading Russian forces, he said, because of what they are doing to his city and his family -- and because they have been relentlessly bombing the city of Kharkiv in northeast Ukraine, where his other grandson is trapped.
Another city under siege by Russia is Mariupol, around 125 miles south of Zaporizhzhia, which is running out of fuel, food and water. Several attempts at evacuation corridors to help civilians escape have failed after Russian forces continued to fire on those routes, Ukrainian officials said.
Many residents of Zaporizhzhia fear the same fate could be in store for their city.
Sergiy and Alyona Samkov, who have two young daughters, said they decided to leave a few days ago.
"When the Russian troops came closer to the Zaporizhzhia region, I decided it was better to get my family out (before) they entered the city itself," 30-year-old Sergiy said. "Because we know that in some cities, like Mariupol, evacuation is impossible. We don't want to wait until we have the same situation."
Knowing that she faced a long journey and may eventually have to cross the final stretch of the Polish border on foot, Alyona traveled light, bringing only a stroller and supplies of food and drinks for their two daughters, 6-year-old Elyna and 7-month-old Emilia. Elyna was also allowed to bring a single cuddly toy -- a bright yellow duck called Luff Luff.
But despite their desperation to leave, the family have failed to get a place on a train for the past two days.
"People didn't let us in even though we had a baby," said Alyona, 35. "We lifted her up, but people were pushing each other and we couldn't make it."
On Saturday, some of those waiting eventually gave up hope and turned around, dragging their wheeled suitcases back along the station platform.
Nearby, the men who said indefinite goodbyes to their wives and children are ashen-faced, dealing with the uncertainty of what could happen to their families on the long journey west, along with the looming threat of their city being invaded by Russian forces.
But many remain defiant -- and ready to fight.
"The main thing for me is to see my family off," Sergiy Samkov said. "I'll defend our city (and) help the territorial defense forces. I will stay here until the end."