Here are the latest developments in the war in Ukraine:

Russian forces are stepping up their offensive around Lugansk in Ukraine's eastern Donbas region, as the conflict enters its fourth month.

Since Moscow's invasion in late February, Western support has helped Ukraine hold off its neighbour's advances in many areas -- including the capital Kyiv -- but Russia is now focused on securing and expanding its gains in Donbas and the southern coast.

"The coming weeks of the war will be difficult, and we must be aware of that," Ukraine's President Volodymyr Zelensky says in his latest nightly address, singling out fierce fighting in three Donbas towns.

Russian Defence Minister Sergei Shoigu says Moscow is nearing full control of the separatist region of Lugansk in eastern Ukraine.

"The liberation of the Lugansk People's Republic is nearing completion," Shoigu says, having earlier revealed Moscow will create new military bases in western Russia in response to the expansion of NATO.

A European agreement on a Russian oil embargo is possible "within a few days", the German economy minister says, as the bloc struggles to reach a consensus on a boycott.

"There are only a few states left who have issues, Hungary above all," Robert Habeck tells public broadcaster ZDF.

"I think we will achieve a breakthrough within the next few days," Habeck predicts, insisting an embargo in response to the invasion of Ukraine is "within reach" despite opposition notably from Hungary, which fears the effect on the security of its energy supply.

Ukrainian forces are battering Russian positions with newly-provided Western artillery systems, according to a Ukrainian military spokesman.

Olga Khomenko, 67, looks for the remains of her son, allegedly killed when a Russian tank shell hit his car outside a village near Kharkiv Olga Khomenko, 67, looks for the remains of her son, allegedly killed when a Russian tank shell hit his car outside a village near Kharkiv Photo: AFP / SERGEY BOBOK

For much of the war Ukraine has relied on their own Soviet-era howitzers but in recent weeks state of the art artillery systems from friendly nations, including the United States' M777, have made their way to the frontline.

Some 20 countries have meanwhile offered new security assistance packages for Ukraine to battle invading Russian forces following a meeting of allies on Monday, US Secretary of Defense Lloyd Austin says.

The lawyer for the first Russian soldier to face trial in Kyiv says his client is "not guilty" of premeditated murder and war crimes and is urging his acquittal after the 21-year-old received a life sentence for killing a civilian days after the invasion.

Sergeant Vadim Shishimarin, at the centre of the first war crimes trial held over the conflict, has said he is "truly sorry" and asked the widow of the Ukrainian civilian he killed for forgiveness.

But the court has given him a life term for what it deemed the premeditated killing of 62-year-old civilian, Oleksandr Shelipov.

President Recep Tayyip Erdogan says he is talking to Western leaders about Turkey's objections to NATO membership for Sweden and Finland, whom he accuses of sheltering Kurdish separatists.

Russia's war in Ukraine has shifted political opinion in both Nordic countries in favour of joining the Western military alliance.

"We cannot say 'yes' to (Sweden and Finland)... joining NATO, a security organisation," Erdogan said.