German police have raided more than 30 sites believed to be connected to a banned Islamic organisation, al-Aqsa.
The charity is accused of having links with Hamas
The raids happened a day after the country's top administrative court upheld a 2002 ban on the group.
The German government alleges that the charity raises funds for the Palestinian militant movement, Hamas.
Al-Aqsa, which says it raises funds to alleviate poverty, had won permission to continue fundraising on a temporary basis last year.
The raids were conducted on 34 sites in Berlin, Bremen, Lower Saxony and North Rhine-Westphalia.
The Interior Ministry says the police seized "extensive" materials.
The German Interior Minister, Otto Schily, said the raids had targeted sites connected with two groups suspected of taking over from al-Aqsa in 2002.
He said if the suspicions were confirmed, he would ban the new groups as well.
On Friday, a German court upheld the original decision to ban the charity, saying there was evidence it provided financial support for attacks by Hamas on Israeli targets.
The group is not believed to be connected to the al-Aqsa Martyrs' Brigade, which linked to the main Palestinian group, Fatah.