"An investigation was opened on April 25 against an Austrian citizen and another as-yet-unidentified individual in connection with possible participation in so-called 'sniper tours' in Sarajevo during the Bosnian war," the justice ministry said in a statement.

Allegations of tourists paying the Bosnian Serb army to let them shoot civilians in the besieged city exploded in 2022, when Slovenian filmmaker Miran Zupanic revealed them in the documentary "Sarajevo Safari".

Italian journalist Ezio Gavazzeni said in a book published last March that the "weekend snipers" included travellers from Italy, France, Belgium, Switzerland, Russia and Austria.

He said their travel was organised through the Milan branch of a Belgium-based security company.

Gavazzeni cited an unnamed former French soldier who said he had accompanied small groups of snipers to Bosnia between 1992 and 1995, "generally people over 50 and well off".

Italian prosecutors opened an investigation last year, and in February questioned an 80-year-old suspect, a former truck driver.

The Austrian justice ministry told local media its investigation was not based on Gavazzeni's research but another source.

During the nearly four-year siege of Sarajevo, which began in April 1992, more than 11,500 men, women and children were killed and more than 50,000 people wounded by Bosnian Serb forces, according to official figures.

In all, around 100,000 people, half of them civilians, died in the Bosnian war, part of the bloody breakup of the former Yugoslavia.