A former British soldier, who was discharged from service in March this year, has died fighting Russian forces in Ukraine, according to a statement from his family.

Jordan Gatley had left the British Army to help Ukrainian forces and "to continue his career as a soldier in other areas," his father, Dean Gatley wrote in a Facebook post on Saturday.

He died defending the eastern city of Severodonetsk, where fighting has lasted for more than three months since Russia has shifted its focus from the capital city of Kyiv.

His father further wrote that his brave son had also been helping train local forces and had taken the decision to help Ukrainian forces "after careful consideration."

"Yesterday (we received the devastating news that our son, Jordan, has been shot and killed in the city of Sievierodonetsk, Ukraine ... He loved his job and we are so proud of him. He truly was a hero and will forever be in our hearts," the statement added.

Mykhailo Podolyak, an adviser to Ukrainian President Volodymyr Zelensky, also paid tribute to Gatley in a Twitter post. "We will always remember his contribution to the protection of Ukraine and the free world," Podolyak wrote. According to a BBC report, Gatley served in the British army as a rifleman with the Edinburgh-based third battalion of The Rifles.

Gatley is reportedly the second Briton to have been killed in the Russia-Ukraine war. Scott Sibley, a British Army veteran, is believed to have died fighting Russian forces in April.

As one of the industrial hubs on Russia's path to taking the eastern Lugansk region, Severodonetsk has become a target of massive Russian firepower since the failed attempt to occupy Kyiv.

Russian and Ukrainian troops are battling for control over Severodonetsk, as seizing the city will allow Russia to move closer to its goal of taking over Luhansk and the Donetsk regions of eastern Ukraine.

Russia says it is on a mission to "liberate" the Donbas - partly held by separatist proxies of Moscow since 2014 - after Ukrainian forces pushed its troops back from the capital Kyiv and Ukraine's second city Kharkiv in the war's early stages.

Russia calls its action in Ukraine a "special military operation" to stamp out what it sees as threats to its security. Ukraine and its Western allies dismiss this as nonsense and say it is an unprovoked war to grab territory that risks turning into a wider European conflict.

Russia's onslaught has wrought has destruction in Ukraine since the February 24 invasion