German police have stormed an accommodation facility for refugees and 12 homes around the country that were believed to house people suspected of financing terrorism.
On Tuesday police searched residences in the eastern states of Thuringia and Saxony as well as in Bavaria, the western state of North Rhine-Westphalia and in Hamburg, police in Thuringia said in a statement.
The investigation has so far not uncovered any concrete risk of attack, they said.
No one was arrested during the raids, a police spokeswoman eastern state of Thuringia said.
A non-dangerous substance had been found and that was now being investigated.
The police have been investigating a 28-year-old Russian citizen of Chechen origin since the second half of 2015 who was suspected of preparing "a serious act of violent subversion", the statement said.
They believed he intended to fight for Islamic State in Syria.
During the course of investigations, suspicion arose that that person as well as 10 other men and three women - all Russian citizens of Chechen origin - were financing terrorism.
The suspects were living in Thuringia, Hamburg and Dortmund, are asylum seekers with unclear residency status, and are aged between 21 and 31, police said.
Earlier this month a Syrian refugee who was arrested on suspicion of planning a major attack in Berlin was found dead in prison after he initially evaded police during a raid on his apartment where 1.5 kg of explosives were found. Authorities said he died by suicide.
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