"Inquiries have shown that Swiss hand grenades delivered to UAE in 2003 and 2004 reached Syria," the Federal Department of Economic Affairs said in a statement, presenting the results of a two-month probe.
Switzerland and the UAE launched the investigation after Swiss media published a photograph of a Swiss-made hand grenade taken by a reporter shadowing rebels north of Aleppo at the end of June.
The probe found that the UAE gave "part" of its munitions delivery to Jordan "to help the country in its fight against terrorism".
"From Jordan, the hand grenades clearly surfaced in Syria," the Swiss economic affairs department said, adding that the UAE had provided a written guarantee that no other munitions were involved.
With the joint Swiss-UAE investigation over, Switzerland would resume its arms exports to the UAE after a temporary freeze, the statement said.
But future exports will take place on a stricter footing to ensure that no other weapons shipments go astray, it added.
Future arms shipments will for instance require written guarantees from "a high-ranking government official" and must be countersigned by a diplomatic note that they will stay put in the purchasing country.
The economic affairs department also said Switzerland intends to tighten its inspections of arms shipments to the UAE, and would reexamine "shipments of arms carried out previously to some countries".
The economic affairs department said previously that the UAE army imported some 225,000 Swiss hand grenades in 2003, stressing that Switzerland has not exported any weapons to Syria since 1998.