The prosecutor-general of the Russian-backed self-proclaimed Luhansk People's Republic (LPR) in eastern Ukraine and his deputy were killed by a bomb blast at their offices on Friday, according to local officials and emergency services.

"According to preliminary data, LNR Prosecutor-General Sergei Gorenko died from his injuries as a result of an explosion at his office," a spokesperson for the emergency services said, according to the Russian news agency Interfax.

The state-run TASS news agency quoted a colonel in the separatist Luhansk interior ministry as saying Gorenko's deputy had also been killed.

Russian agencies quoted emergency services and local officials as saying the blast had been caused by a bomb.