German police on Sunday raided the apartments of two men suspected of having links to a militant organization, a spokesman for the Federal Prosecutor Office said.
The raid took place near the city of Mainz in western Germany. The two men are suspected of having taken part in the Syrian civil war as members of a foreign terrorist organization, the spokesman said.
"We do not have any indication of concrete attack plans," the spokesman said, referring to the possibility that the men may have been planning attacks in Germany.
He said the two men had been questioned but declined to give any further details.
German news website Spiegel Online reported that one of the men was suspected of being a high-ranking commander in the Islamic State group.
It said the 32-year-old was suspected of having fought with Islamic State in the eastern Syrian city of Deir ez-Zor, then traveling through Turkey and arriving in Germany last autumn.
On Thursday, German police conducted raids in Berlin and other parts of northern Germany and arrested two men suspected of links to Islamic State and of preparing an attack in the German capital.