Firefighters work to extinguish a fire at a damaged logistics center after shelling in Kyiv, Ukraine,

Russian forces took control Thursday of the strategic Ukranian port city of Kherson as they continued to shell major cities in an offensive that has forced more than 1 million people to flee the country.

Local government officials and the Russian military confirmed the seizure of Kherson, the first city to fall in Russia’s week-old invasion of Ukraine, following days of disputed claims over who was in control.

Moscow’s attempt to quickly take over the Ukrainian capital has apparently stalled, but the military has made significant gains in the south as part of efforts to sever the country’s connection to Black and Azov seas.

Despite Russian assaults on Kharkiv, Chernihiv and Mariupol, Britain’s Defense Ministry said Thursday they all remained in Ukrainian hands.

“We are a people who in a week have destroyed the plans of the enemy,” Ukrainian President Volodymyr Zelenskyy said in a video address early Thursday. “They will have no peace here. They will have no food. They will have here not one quiet moment.”

Russian troops were also besieging the port city of Mariupol east of Kherson, an attempt Mayor Vadym Boichenko said was aimed at isolating Ukraine.

“They are trying to create a blockade here,” Boichenko said Thursday in a broadcast video. He said the Russians are attacking rail stations to prevent civilian evacuations and that the attacks have cut off water and power.

Ukraine’s Defense Minister Oleksii Reznikov cited expectations ahead of the invasion that Russia would quickly overtake Ukraine, writing on Facebook, “No one, neither in Russia nor in the West, believed that we would last a week.” He added that while there are challenges ahead, Ukraine has “every reason to be confident.” (AP/VOA)