A man has been arrested in Germany on suspicion of procuring the deadly poisons cyanide and ricin to be used in an "Islamist-motivated" attack, authorities have 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," a joint press release from the Dusseldorf public prosecutor's office and local police said.
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."
A second individual, confirmed to be the suspect's brother, was also detained as part of the searches.
Police raided the suspect's home following a tip-off from an agency of what German officials described as a "friendly state".
Though police did not confirm the identity of the state, the German tabloid Bild said the agency in question was the FBI.
German police seized electronic devices during the raid.
However they did not find cyanide or ricin during the search, Holger Heming of the Dusseldorf public prosecutor's office told reporters.
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 supposedly 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 also toxic to humans and animals.
Though deadly, it is used in the mining of silver and gold to separate the metals from other solids.