Two suspected Islamists were arrested early Thursday in a series of coordinated raids across Germany prompted by a tip-off of a terrorist attack, security sources told dpa.
The raids were conducted in homes and businesses in Berlin, as well as refugee registration centres in Hanover and the town of Attendorn in North Rhine-Westphalia.
Two out of four Algerian suspects wanted by police are now in custody. The main suspect, a 35-year-old Algerian man, was apprehended in the Attendorn registration centre, while the other was taken into custody in the German capital, police said.
The remaining two suspects - a 31-year-old and a 26-year-old thought to be located in Berlin and Hanover respectively - have yet to be apprehended.
Police confirmed that the suspects were found to have links to Islamic State and that the main suspect had attended a training camp in Syria.
Police received a tip-off of a terrorist attack from Germany's domestic intelligence agency, the Verfassungsschutz. Investigations have been ongoing for several weeks.
Police had information that the suspects were planning to meet in Berlin to plan terrorist attacks. It is not known whether the plans were close to fruition.
Police also detained a woman during the raids in Berlin, but the case is unrelated to the terrorist threat. There had been a warrant for her arrest.
Frank Henkel, Berlin's senator of the interior, said that the threat of a terrorist attack remained high. "We continue to have every reason to remain vigilant and careful," he said.