An Iranian man has been arrested in Germany on suspicion of procuring cyanide and ricin to be used in an “Islamist-motivated” attack following a tip from US security officials, authorities said on Sunday.
The 32-year-old was detained overnight in the town of Castrop-Rauxel, northwest of Dortmund.
Police raided his home and seized electronic devices but no deadly poisons were found.
Specialists wearing anti-contamination suits were seen carrying evidence out of the property.
The suspect’s brother was also held and the pair remain in custody.
A joint press release from the Düsseldorf public prosecutor’s office and local police said: “The suspect is suspected of having prepared a serious act of violence endangering the state by allegedly procuring cyanide and ricin to commit an Islamist-motivated attack.”
Germany’s interior minister Herbert Reul added: “We had a serious tip-off that prompted the police to intervene during the night.
“The authorities are now investigating at full speed.”
The tip-off came from what German officials described as a “friendly state”. Later, Duesseldorf prosecutors confirmed it was from authorities in the United States, but declined to elaborate.
German tabloid Bild said the agency in question was the FBI.
Ricin is a highly potent toxin produced in the seeds of the castor oil plant, which is indigenous to areas of the Middle East, eastern Africa and parts of India.
It can cause death within 36 to 72 hours from exposure to an amount as small as a pinhead.
The poison is believed to have been used in the 1978 assassination of Bulgarian dissident Georgi Markov in London.
It was reportedly administered through a pellet fired into Mr Markov’s leg by a member of the Bulgarian Secret Service using a specially crafted umbrella, which it was later claimed was developed by the KGB.
Similarly, cyanide which can be found naturally in some seeds and fruit stones is toxic to humans and animals.
Germany’s Deutsche-Presse news agency reported numerous emergency workers in protective suits attending the scene.
The investigation is continuing, however, it is unclear how far the attack plans had progressed.
Düsseldorf senior public prosecutor Holger Heming said he would not speculate on the possible target of the suspected attack.
“After an evaluation of the information, we came to the conclusion to issue a search warrant and carry it out as soon as possible,” Mr Holger Heming told reporters.
Deutsche-Presse cited an unidentified German security official as saying there was no indication the suspect had acted on behalf of the Iranian state, but rather that he allegedly supported a Sunni extremist group. Sunnis are a religious minority in Iran.
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.