LONDON: A former British soldier has been killed fighting for Ukraine in the city of Sievierodonetsk, his family said on social media, and a senior Ukrainian official praised him as a "true hero".

Jordan Gatley left the British Army in March, his family said, and went to Ukraine to help in the fight against the Russian invasion.

The family said it had received the news on Friday that he had been shot and killed.

The eastern city is the epicentre of intense fighting to control the country's Donbas region.

"He loved his job and we are so proud of him," his family said in a Facebook post. "He truly was a hero and will forever be in our hearts."

Ukrainian presidential adviser Mykhailo Podolyak paid tribute to Gatley, saying it took a lot of courage to travel far from home to defend beliefs.

"Just because the heart says so. Because you can't stand the evil. Jordan Gatley was a true hero. We will always remember his contribution to the protection of Ukraine and the free world," Podolyak wrote in a Twitter post.

Britain's Foreign Office said: "We are supporting the family of a British man who has died in Ukraine."

The Ukrainian Defence Ministry did not immediately respond to a written request for comment. (Reporting by Paul Sandle Editing by Frances Kerry and Angus MacSwan)