Geneva - Swiss authorities said on Saturday that two people of Syrian origin had been arrested on suspicion of transporting "explosives and toxic gases" as part of a probe into a terror threat.
The two suspects arrested on Friday are accused of the "manufacture, concealment and transport of explosives and toxic gases", the federal prosecutor's office said in a statement.
They are also under suspicion of violating Swiss law prohibiting "groups like al-Qaeda, the Islamic State and similar organisations", it added.
Several Swiss media reported earlier that two people had been arrested in the Geneva region and that traces of explosives were found in their car, as the western city remained on alert due to an increased jihadist threat.
The Geneva region raised its alert level to three on a five-point scale on Thursday and armed police were deployed at sensitive locations across the city, which is home to the UN's European headquarters.
Geneva is almost entirely enclosed by France, a country still reeling from the jihadist attacks that left 130 people dead in Paris last month.