Authorities arrested two Syrian nationals Friday in Geneva when traces of explosives were found in their vehicle, Swiss media reported.
Authorities in the Geneva region had been searching for four suspected jihadists with alleged ties to the Islamic State, but police did not say whether Friday's arrests were connected to the search. No details were provided on the identities of the two men or the exact location where their car was stopped.
Swiss police increased the terror alert level in the city Thursday. Authorities said they were acting on information from Swiss federal officials that "suspicious individuals" believed to be connected to the Nov. 13 Paris attacks "could be in Geneva or the Geneva region."
France's neighboring countries have tightened their security measures since the Paris attacks, which left 130 people dead and more than 350 injured. The Islamic State extremist group claimed responsibility.
One suspect linked to the attacks is still at large.