German police carried out a series of raids early Wednesday at locations associated with three suspected supporters of the Islamic State group, the federal prosecutor's office said.
The men are suspected of recruiting people on behalf of Islamic State between January and July 2015. One of them is suspected of providing financial and logistical support to the terrorist group, a spokeswoman said.
Police in the western German states of North Rhine Westphalia and Lower Saxony confirmed on Wednesday that the raids had taken place in Dortmund, Duisburg and Hildesheim.
Online media outlet DerWesten reported that one of the men, the proprietor of a travel agency that was raided early Wednesday, has suspected links to two people planning an attack on a Sikh temple in the city of Essen.
Late Tuesday, police in the state of Rhineland-Palatinate announced the arrest of a 24-year-old asylum seeker suspected of membership in Islamic State and of acting on behalf of a high-ranking member of the terrorist organization.
The arrest came in connection with alleged threats against the German Bundesliga football league, which is expected to kick off its season later this month.
Germany has been on high alert since four violent attacks in the space of one week last month - two of them claimed by Islamic State - left 12 people dead, three of them attackers.