Here are the latest developments in the war in Ukraine:

A Ukrainian court convicts a 21-year-old Russian soldier of war crimes and sentences him to life in prison at the first trial held over Russia's invasion of its neighbour.

Vadim Shishimarin admitted to shooting dead 62-year-old civilian Oleksandr Shelipov in the early stages of Moscow's invasion. His lawyer says he will appeal.

Ukrainian President Volodymyr Zelensky urges the international community to halt all trade with Russia, shun its banks and IT sector and impose an oil embargo.

In an address by video-link to political and business leaders attending the World Economic Forum in Davos, he tells delegates: "There should not be any trade with Russia."

He also argues that tens of thousands of lives could have been saved if Kyiv had received "100 percent" of its weapon requests.

US President Joe Biden says Russia must "pay a long-term price" for its "barbarism in Ukraine".

Polish President Andrzej Duda, on a visit to Kyiv on Sunday, also says there can be no "business as usual" with Russia after the massacre of civilians in places such as the Kyiv suburb of Bucha and the southeastern port of Mariupol.

Ukraine has extended its martial law as the war with Russia drags on Ukraine has extended its martial law as the war with Russia drags on Photo: AFP / Olga MALTSEVA

In the eastern city of Severodonetsk Lugansk regional governor Sergiy Gaiday accuses Russian forces of "using scorched-earth tactics, deliberately destroying" the city.

Gaiday says Russia is redeploying forces from the northeastern Kharkiv region and the siege of the conquered city of Mariupol as well as pro-Russian separatist militias and troops mobilised from Siberia to the fight for the Lugansk and neighbouring Donetsk regions, which have become the focus of Moscow's campaign.

Ukraine's First Lady urges the World Health Organization to help tackle the country's vast mental health crisis, warning that the effects of the three-month-old war could last for decades.

"Following what Ukrainians have experienced during the occupation, at the front, in bomb shelters, under shelling... they need rehabilitation in the same way as those who are physically wounded," Olena Zelenska tells the WHO's annual assembly.

Starbucks says it will cease operations in Russia, shuttering its 130 cafes in the country.

Last week, McDonald's announced it was leaving Russia after more than 30 years.

Ukraine extends martial law and the general mobilisation of the population for three months through to August 23.

Authorities in the Moscow-controlled southern Ukrainian region of Kherson announce the introduction of the ruble as an official currency alongside the Ukrainian hryvnia.

The region's capital Kherson was the first major city to fall to Russian forces.