Two Iranian brothers were arrested in western Germany accused of planning an "Islamist attack" using lethal toxins, prosecutors said Sunday.
The men were accused of "planning to carry out an Islamist attack in which they wanted to obtain toxins — cyanide and ricin — in order to kill an indefinite number of people," the prosecutor's office said in a statement.
The brothers, aged 32 and 25, were referred to by the Duesseldorf prosecutor's office as "MJ" and "JJ" respectively.
An initial search of the men's residence in Castrop-Rauxel did not uncover any traces of the toxic substances, Duesseldorf prosecutor Holger Heming told AFP.
The two men would however be charged with "conspiracy" to commit murder, a crime which could carry a prison sentence of between "three to 15 years," prosecutors said.
Agents wearing protective suits against the potential chemical hazard carried out the raids in Castrop-Rauxel overnight into Sunday.
Images from the news channel NTV, showed the two men being led away in their underwear with jackets thrown over their shoulders.
"Our security forces take every suggestion of Islamist terror threats very seriously and act accordingly," federal Interior Minister Nancy Faeser said in a statement.
Authorities had been given a "serious tip" that prompted the overnight raid, said Herbert Reul, interior minister for the North Rhine-Westphalia region.
The German security services were alerted to the chemical terror threat by colleagues from the FBI, according to local media reports.
The American security services are said to have infiltrated a Telegram chat group where the two suspects "asked about bomb construction plans and later about toxins," according to a report from Spiegel weekly.
Ricin is a highly toxic substance that is classified as a "chemical weapon" in Germany.
Produced by processing castor beans, ricin is lethal in minute doses if swallowed, inhaled or injected and 6,000 times more potent than cyanide, with no known antidote.
In 2018, a Tunisian man and his wife were arrested on suspicion of planning a chemical attack in Germany.
The couple, who sympathized with the Islamic State group, were found in possession of 84 milligrams of ricin in their Cologne apartment.
The pair had ordered castor seeds, explosives and metal ball bearings on the internet to build a toxic bomb.
The man was sentenced to 10 years in prison in 2020, while his wife received an eight-year sentence.
Germany has been targeted in recent years by several Islamist attacks, including a 2016 truck attack on a Christmas market that killed 12 people and left dozens injured.
A 13th victim died five years later having suffered serious injuries in the assault.