Aiden Aslin was among five men released as part of a prisoner swap
Aiden Aslin was among five men released as part of a prisoner swap AFP

Five British men released from detention by Russian-backed separatists in Ukraine in a prisoner swap, are now back home, a group campaigning for their liberation said Thursday.

"We know that all are back safely in the UK now and looking forward to normality with their families after this horrific ordeal," humanitarian organisation Presidium Network said in a statement emailed to AFP.

Prime Minister Liz Truss tweeted Wednesday that the men's release was "hugely welcome".

Five British men -- Aiden Aslin, Shaun Pinner, Dylan Healy, John Harding and Andrew Hill -- were released as part of a record-high prisoner swap that also freed US, Moroccan, Swedish and Croatian nationals as well Ukrainian and separatist fighters and a major pro-Moscow politician.

Aslin told journalists on his doorstep in Newark in eastern England: "I just want to say I want to thank President (Volodymyr) Zelensky and the Saudi authorities and everyone else that was involved in our release.

"In the next few days, the rest of us will say what we need to say to the media," he said, asking for privacy "after the traumatic experience that we have just been through".

Aslin stood beside a hand-drawn sign saying "Welcome home Aiden".

Pinner's family released a photo of him smiling and hugging family members.

The freed prisoners were flown out to Riyadh on Wednesday after Crown Prince Mohammed bin Salman took part in negotiations.

The British men had been held by Russian proxies in the separatist hub of Donetsk after joining the war as volunteer fighters and aid workers.

Aslin and Pinner were sentenced to death in June, while the other three men went on trial in August on the same charge of serving as mercenaries.

One British man, Paul Urey, died in captivity after being detained shortly after the war began in April.

Ukraine's Foreign Minister Dmytro Kuleba said this month that the aid worker's body had been handed to Kyiv and showed "signs of possible unspeakable torture".

His mother Linda Urey posted on Facebook of the prisoner release: "I'm happy for those involved however I'm devastated that my son is not one of them."

Urey's family have been crowdfunding to raise money to repatriate his body.

His mother wrote that his body is still in Kyiv "lying in a freezer almost three months dead".

Britain's foreign minister James Cleverly said Wednesday that "our thoughts remain with the family of Paul Urey".