"It is with deep regret that we must announce that a member of the UK Armed Forces died in Ukraine this morning," the Ministry of Defence said.

It marked the first time a member of the UK military had been killed in Ukraine since Russia's February 2022 invasion, it said.

"He was injured in a tragic accident whilst observing Ukrainian forces test a new defensive capability, away from the front lines," it added.

"My deepest sympathy and condolences to the family of the member of our Armed Forces who sadly lost their life today," UK Prime Minister Keir Starmer said in a statement.

"Their service and sacrifice will never be forgotten."

The UK has previously said there are a "small number" of UK troops in the country supporting Ukrainian forces.

An ex-British soldier who was volunteering with the Ukrainian army was killed far from the frontline in 2023. A UK coroner's inquest last year found that he was killed by a "comrade" also volunteering with the Ukrainian forces.