German authorities conducted raids across the country on Wednesday, seizing explosives and arresting four people accused of founding a right-wing extremist group to attack mosques and housing for asylum seekers.

Police arrested three men and a woman accused of leading the group during raids by some 250 investigators on homes in Saxony and four other states, the federal prosecutor's office said in a statement.

Prosecutors allege the four helped found the “Old School Society” group and were planning to attack asylum-seeker housing, mosques and well-known members of the Islamic-extremist Salafist scene in Germany.

The four arrested, identified only as Andreas H., 56, Markus W., 39, Denise Vanessa G., 22, and Olaf O., 47, are being held on terrorism charges and are also accused of having procured explosives.

The statement identified Andreas H. and Markus W. as the group's president and vice president.

“According to current investigations, it was the group's goal to conduct attacks in smaller groups inside Germany on well-known Salafists, mosques and asylum seeker centers,” the statement said. “For this purpose the four arrested procured explosives for possible terror attacks by the group.”

Prosecutors said they are still trying to determine whether the group had concrete attack plans and refused to comment beyond their written statement.

Opinion polls have long shown high anti-Islamic bias among Germans — numbers roughly the same as those across Northern Europe. In a survey conducted by the Forsa Institute for Social Research and Statistical Analysis, 52 percent of Germans said, “Islam doesn’t belong to Germany” (60 percent among easterners, 61 percent among young people, 61 percent among seniors). A similar study by the University of Leipzig found an upswing in anti-Muslim, anti-immigrant and anti-Roma sentiments across Germany, with 43 percent of Germans saying they felt alienated because of the presence of large numbers of Muslims in the country.

Right-wing extremists have been a renewed focus for German intelligence agencies after it came to light that a neo-Nazi group calling itself National Socialist Underground, or NSU, allegedly killed eight Turks, a Greek and a policewoman between 2000 and 2007. It is also believed to be behind two bombings and 15 bank robberies.

The group's sole survivor, Beate Zschaepe, and four alleged supporters are currently on trial in Munich.

The group's existence only came to light in late 2011, after Zschaepe's alleged accomplices, Uwe Mundlos and Uwe Boenhardt, died in an apparent murder-suicide following a botched bank robbery.

Dresden, the capital of Saxony, where many of the raids were conducted on Wednesday, has been a hotbed of neo-Nazi activity ever since the end of communism in 1989.

But Saxony’s immigrant population is small compared with those of other parts of Germany. At just over 100,000, immigrants make up an estimated 2.8 percent of the state’s 4 million residents, compared with more than 14 percent in big cities like Berlin and Hamburg. Reportedly, just 0.1 percent are Muslims.

The anti-immigrant group, PEGIDA, Patriotische Europäer gegen eine Islamisierung des Abendlandes (Patriotic Europeans Against the Islamicization of the West), held weekly demonstrations in Dresden last winter, which sparked counterdemonstrations.

German Chancellor Angela Merkel urged Germans to shun the anti-Muslim protesters, saying their hearts are full of hatred and argued that hostility towards foreigners has no place in Germany.

Al Jazeera with the Associated Press