Ukraine vows to fight to the end in Mariupol as ultimatum expires

Ukraine on Sunday vowed to fight to the end in Mariupol after a Russian ultimatum expired for remaining forces to surrender in the Black Sea port city where Moscow is pushing for a major strategic victory.

"The city still has not fallen," Prime Minister Denys Shmyhal said hours after Moscow's deadline had passed for fighters holed up and surrounded in a sprawling fortress-like steelworks to surrender.

"There's still our military forces, our soldiers. So they will fight to the end," he said "This Week".

Moscow has shifted its military focus to gaining control of the eastern Donbas region and forging a land corridor to already-annexed Crimea. 

Russia's defence ministry said there were up to 400 mercenaries inside the encircled Azovstal steel plant, calling on Ukrainian forces inside to "lay down their arms and surrender in order to save their lives". 

Moscow claims Kyiv has ordered fighters of the nationalist Azov battalion to "shoot on the spot" anyone wanting to surrender. 

Ukraine President Volodymyr Zelensky said if Russian forces killed the remaining troops defending the city, it would end the peace talks.

Russian President Vladimir Putin has already said the talks are at a "dead end".

Shmyhal said Ukraine wanted a diplomatic solution but would fight to the end if necessary. "We will not surrender."

While several large cities were under siege, he said, not one -- with the exception of Kherson in the south -- had fallen, and more than 900 towns and cities had been liberated.

As Russia scales up attacks on Ukraine's eastern flank, at least five people were killed and 20 wounded in a series of strikes in second city Kharkiv, just 21 kilometres from the Russian border.

Russian forces continued to shell the eastern Lugansk region and two people died in the town of Zolote, governor Sergiy Gaiday told Ukrainian media.

In addition, two people died and four were wounded in attacks on the towns of Marinka and Novopol, west of Donetsk, regional governor Pavlo Kyrylenko said on Telegram; and an airstrike hit an armaments factory in the capital Kyiv.

Maksym Khaustov, the head of the Kharkiv region's health department, confirmed the deaths there following a series of strikes that journalists on the scene said had ignited fires throughout the city and torn roofs from buildings.

"The whole home rumbled and trembled," 71-year-old Svitlana Pelelygina said as she surveyed her wrecked apartment. "Everything here began to burn."

"I called the firefighters. They said, "We are on our way but we were also being shelled."