Members of the Islamic State group came into possession of Swiss grenades during the conflict in Syria, according to a Sunday report by SonnstagsBlick.
The report claims the war ordinance reached Syria via the United Arab Emirates.
The German-language newspaper published photographs taken in early August by fighters of the jihadist alliance Hayat Tahrir al-Sham (HTS) near the disputed town of Idlib in northern Syria.
The photo shows an arsenal of weapons allegedly seized by HTS, which was formed by members of the former al-Qaeda branch in Syria, during an attack on a cell of rival Islamic State militants.
The weapons include home-made bombs, rifles, explosive belts and Swiss grenades of the OHG92 and HG85 types.
According to the newspaper, the ammunition was part of a delivery approved by the State Secretariat for Economic Affairs (SECO)external link in 2003 to the United Arab Emirates.
The latter, violating the principle of re-export, reportedly sold the arms to Jordan, from where they arrived in Syria in 2012.
The Swiss government in June decided to soften the rules on arms exports, a move that would make exports to countries with an internal armed conflict possible under certain conditions.
On Saturday, the head of Swiss-run International Committee of the Red Cross (ICRC) criticised this course of action.