Russian forces have seized the eastern Ukrainian city of Kreminna and forces are clashing along a 480-kilometre front line in the Donbas region.

Russia claims it has attacked 1000 Ukrainian positions in the east on night one of its “next phase of war” and there are reports it has sent up to 11,000 more soldiers to join the fight.

The United Nations Secretary General, Antonio Guterres, has condemned that Russian offensive and called for a four-day “humanitarian pause” to allow aid workers a safe corridor to reach innocent Ukrainians.

Western leaders are also making calls on Wednesday morning – speaking together about a new round of financial and military support.

Here’s a wrap of the latest out of Ukraine.

Russia seizes eastern city

Kreminna – a city of more than 18,000 people, about 575 kilometres south-east of the capital Kyiv – appears to be the first city captured in a new Russian offensive in eastern Ukraine.

“Kreminna is under the control of the ‘Orcs’ [Russians]. They have entered the city,” Serhiy Gaidai, the governor of the Luhansk region, said.

“Our defenders had to withdraw. They have entrenched themselves in new positions and continue to fight the Russian army.”

He said Russian forces had attacked “from all sides”.

“It is impossible to calculate the number of dead among the civilian population,” Mr Gaidai said.

“We have official statistics – about 200 dead – but in reality there are many more.”

New phase of war

The New York Times reports the Pentagon estimates that Russia has already deployed an additional 11 battalion tactical groups – likely to comprise 8000-11,000 soldiers.

Moscow also has tens of thousands more fighters in reserve north of Ukraine who are being rested and resupplied to join the attacks, American officials said.

“Another phase of this operation is starting now,” Foreign Minister Sergey Lavrov said, as Russia’s Defence Ministry announced that its missile and artillery forces had struck hundreds of Ukrainian military targets overnight.

Tweet from @DefenceHQ

Defence Minister Sergei Shoigu said Russia was “methodically” carrying out its plan to “liberate” Donetsk and Luhansk, regions that Moscow demands Ukraine cede fully to Russian-backed separatists.

Driven back by Ukrainian forces in March from an assault on Kyiv in the north, Russia has instead poured troops into the east for the Donbas offensive.

It has also made long-distance strikes at other targets, including the capital.

Ukraine’s top security official, Oleksiy Danilov, said Russian forces had tried to break through Ukrainian defences “along almost the entire front line of Donetsk, Luhansk and Kharkiv regions”.

Russia now says its aim is to capture the full provinces on the separatists’ behalf.

Ukraine has a large force defending northern parts of the Donbas and military experts say Russia aims to cut them off or surround them.

But Russia still needs to keep its troops supplied across kilometres of hostile territory.

Ukraine has counter-attacked near Kharkiv in the rear of Russia’s advance, apparently aiming to cut off supply lines.

In Mariupol, scene of the war’s heaviest fighting and worst humanitarian catastrophe, a last group of Ukrainian defenders holding out in the Azovstal steel works defied Russian calls to surrender and be spared.

However, about 120 civilians living next to the sprawling plant left via humanitarian corridors, the Interfax news agency reported on Tuesday, quoting Russian state TV.

Ukraine said the fighting in the east was preventing evacuations of civilians who remain trapped in cities where food and supplies are running out.

It’s estimated 12 million people need help.

Truce would allow safe passage of aid