Bavarian police said on Thursday they have arrested two men, an Iraqi and a Nigerian, on suspicion that they may have been preparing a "serious act of violence", The Associated Press reported.
The state criminal police office said the 46-year-old Iraqi and the 29-year-old Nigerian were detained in Munich and nearby Fuerstenfeldbrueck, following a tip to Bavarian security authorities.
They did not elaborate, but the Sueddeutsche Zeitung daily quoted Munich prosecutor Thomas Steinkraus-Koch as saying there had been indications the two were in contact with members of the Islamic State (ISIS) group.
Police stressed that no suspicious objects have been found and that there was no "concrete danger to the population" as far as authorities know.
In February, German police arrested three Algerians suspected of links to ISIS after raids targeting several sites, including refugee shelters where some of the suspects lived.
In December, two former ISIS jihadists, including a would-be suicide bomber, were sentenced to jail by a German court on charges of involvement in a terrorist group.
The two were "involved in the Islamic State of Iraq and Syria organization between June and August 2014, and were therefore members of a terrorist group abroad," the court in western Germany's Lower Saxony said in its ruling.
Germany has announced a ban on ISIS in an attempt to prevent the group from recruiting young jihadists in the country.