Spanish authorities are searching the Barcelona home of a Syrian detained in Switzerland, who allegedly traveled in a car found with traces of explosives.

The Interior Ministry said in a statement Wednesday that the search was aimed at uncovering evidence about the suspect and another Syrian detained in Geneva on Dec. 11.

Those arrests came after Swiss authorities stepped up vigilance during a hunt for at least four suspects allegedly linked to the radical Islamic State group and believed to be plotting a specific attack.

The Geneva prosecutor later said the Syrians were not linked to those four, but were also suspected of violating a ban on radical groups.

The Spanish ministry identified the suspects only as A.A., 19 years old; and K.A., 24, and said one holds Spanish residency.