The Attorney General (OAG) confirmed reports Sunday that it had closed its investigation into part of the matter, after determining that the Swiss company's actions did not violate the law.

The ruling, first divulged by the NZZ am Sonntag weekly, followed a probe that was opened in July, a month after the foreign ministry pressed charges against the company and banned it from further operations in the two countries.

The Swiss foreign ministry said at the time that the conduct of Pilatus in Saudi Arabia and UAE was "incompatible with the federal government's foreign policy objectives".

The Saudi and UAE air forces are key components of the Arab coalition that has bombed Iran-backed Huthi rebels in Yemen since 2015, a campaign that has partly triggered what the UN calls the world's worst humanitarian disaster.

In 2017, Pilatus signed a five-year maintenance contract on a fleet of 55 jets it sold to the Saudi military, while the UAE has bought 25 jets from the company which it uses to train pilots.

The company's work in the two countries "qualify as logistical support for armed forces" and must be "discontinued", the foreign ministry said in June.

At the same time, the ministry questioned whether Pilatus was in breach of the obligation to declare its activities.

That part of the matter was then passed on to the OAG, which according to the November ruling obtained by AFP found no law had been broken.

It noted that because the economy ministry had issued temporary export permits and the government was aware of the services Pilatus was providing, there was no need to officially inform Bern.

The foreign ministry did not immediately respond to requests for comment, and it remained unclear whether the OAG's decision to drop the case could impact the ban on Pilatus activities in Saudi Arabia and the UAE.

Swiss parliamentarians recently passed two motions asking Bern to rethink its interpretation of the so-called "mercenaries law" and thus allow Pilatus to resume its activities, but the government rejected them, the ATS news agency reported.

Founded in 1939, Pilatus employs around 2,000 people in central Switzerland, with a focus on aircraft production and services.