A 32-year-old Iranian man has been arrested in Germany for allegedly plotting an “Islamist-motivated” attack.
The man had been plotting to use cyanide and ricin to commit a “serious act of violence”, North Rhine-Westphalia police said in a statement.
They raided the man’s Castrop-Rauxel residence, in the Ruhr region, but prosecutors said no poison was found.
The suspect’s brother was also arrested and the pair remain in custody.
While they did not find poison, police did seize electronic devices from the residence.
A Düsseldorf senior public prosecutor said the tip-off about the man came from a friendly foreign intelligence service.
“After an evaluation of the information, we came to the conclusion to issue a search warrant and carry it out as soon as possible,” Holger Heming told reporters.
Germany’s Deutsche-Presse Agence (dpa) reported numerous emergency workers in protective suits attending the scene.
The investigation is continuing and it was initially unclear how far the attack plans had progressed.
Mr Heming said he would not speculate on the possible target of the suspected attack and that police would decide whether to issue an official arrest warrant at a later date.
The charge of a “serious act of violence endangering the state” is punishable by a prison sentence of between six months and 10 years.
Germany has been the target of numerous Islamist attacks in recent years. In 2016, a truck attack on Christmas markets in Berlin killed 12 people and left dozens injured.