Croatia's foreign ministry "strongly condemned" the indictment against Croatian national Vjekoslav Prebeg who has been charged with mercenary activities by the prosecutors of the Russia-aligned breakaway territory Donetsk People's Republic (DPR) in Ukraine, state news agency Hina said on Wednesday citing a press release.

Croatia “rejects the indictment and does not consider it to be legally sound because it is contrary to international law and conventions on the treatment of captured civilians and prisoners of war,” the ministry said in an unsigned press release.

“The ministry and competent services are in constant contact with the Ukrainian authorities and other partners in order to shed light on the case and have Prebeg released,” they said, adding that they had been in touch with Prebeg’s family.

Hina cited Croatian media reports saying that Prebeg was arrested in May near Mariupol, where he fought for Ukrainian forces against Russian-backed separatists. He has been charged with “terrorist training, participation in the conflict as a mercenary, joining a coup, and subversion of the constitution,” by DPR authorities, charges which allegedly may carry a death sentence or life imprisonment.