Mariupol besieged but not fallen: Ukrainian PM

Ukrainian Prime Minister Denys Shmyhal said Sunday in an exclusive interview with ABC "This Week" that the besieged city of Mariupol has not yet fallen despite Russian demands that Ukrainians surrender.

"There [are] still our military forces, our soldiers, so they will fight until the end," Shmyhal told "This Week" Anchor George Stephanopoulos.

Mariupol is a strategic city for Russia because it would allow Russian forces in the south to connect with troops in the Donbas region. It would also give Russia a key port.

Shmyhal said even though the city remains in Ukrainian control, its residents are suffering.

"They have no water, no food, no heat, no electricity," Shmyhal said. "They ask all of our partners to support and help stop this humanitarian catastrophe."

During a virtual address overnight, Ukrainian President Volodymyr Zelenskyy said Russia's actions in Mariupol were "just inhuman."

"Russia is deliberately trying to destroy everyone who is there in Mariupol," Zelenskyy said.

The Russian Defense Ministry warned that the military would kill any remaining Ukrainian fighters who did not surrender before the overnight deadline.

NATO Secretary-General Jens Stoltenberg said Thursday that Russia is regrouping and repositioning forces to the east, warning that "a big Russian offensive" is expected in the Donbas region in southeastern Ukraine.

Austrian Chancellor Karl Nehammer met with Russian President Vladimir Putin in Moscow last week. Nehammer was the first European leader to do so since Russia invaded Ukraine.

Stephanopoulos asked Shmyhal about the Austrian chancellor's assessment that Putin believes he is winning the war. "Has the tide turned?" he asked.

Shmyhal replied that only one big city "is under control of Russian military forces. But all of the rest of the cities are under Ukrainian control."

On Saturday, Russia continued attacks across Ukraine, including in the capital, Kyiv. The Ukrainian president's office reported missile strikes and shelling in eight regions across the country.

Stephanopoulos asked Shmyhal if peace talks between Ukraine and Russia have reached a dead end.

Shmyhal said Ukraine was open to diplomacy, but if Russia does not want to negotiate, Ukraine will continue to fight.

"We will not surrender; we will not leave our country, our families, our land," Shmyhal said. "So we will fight absolutely to the end, to win in this war."

President Joe Biden authorized $800 million more in military aid last week, after referring to Russia's actions in Ukraine as "genocide." Stephanopoulos asked the Ukrainian Prime Minister what more the country needs.

"We are so grateful to American people, especially to President Biden for [the] support of Ukraine," Shmyhal said. "Only half of our economy is working, so we ask for financial support."

Reuters has reported that Shmyhal will travel to Washington, D.C., this week along with other top Ukrainian finance officials for the International Monetary Fund and World Bank spring meetings.

Shmyhal told Stephanopoulos that while members of his financial team are in Washington, they will continue to push for additional financial support.

Stephanopoulos asked Shmyhal what his message is for the West.

"We need more sanctions from West partners. We need more ammunition to protect our country and European borders," Shmyhal added.

ABC News' Christine Theodorou contributed to this report.