A plot to carry out a biological attack using ricin has been foiled in Germany, officials say.

A 29-year-old Tunisian, identified only as Sief Allah H, was arrested on Wednesday before a search took place in his apartment in Cologne.

Investigators say he started procuring material online including seeds needed for the creation of ricin in mid-May. They said he succeeded in creating the toxin this month and investigators found it in the search of his flat.

They are still investigating how the suspect planned to use the toxin, but said he was working on an attack in Germany.

A plot to carry out a biological attack using ricin has been foiled in Germany, officials say. Police are pictured in special protective clothes at a flat in Cologne earlier this week

A 29-year-old Tunisian, identified only as Sief Allah H, was arrested on Wednesday before a search took place in his apartment in Cologne. Police are pictured at the scene

German news weekly Der Spiegel reported that Sief Allah H. was thought to have been following instructions disseminated by ISIS on how to build a bomb containing ricin.

But prosecutors said they have no evidence of a connection with any extremist organisation.

They did not comment on a report that American intelligence tipped off German investigators.

Prosecutors are still investigating how the suspect planned to use the toxin, but said he was working on an attack in Germany

The deadly toxin with no known antidote Ricin, which has no known antidote, is one of the world's most lethal toxins and is 6,000 times more powerful than cyanide. According to the US Centers for Disease Control and Prevention, the toxin, found naturally in the shell of a variety of bean, works by getting inside cells and preventing them from making proteins they require. Without the proteins, cells die and this can be fatal. Symptoms of poisoning may occur between four and 24 hours depending on exposure with death taking place between 36 and 72 hours, the organisation says. It advises anyone exposed to the toxin to remove their clothing, quickly wash their entire body with soap and water, and seek immediate medical care. Advertisement

He procured 1,000 seeds from a variety of bean online as well as an electronic coffee grinder, prosecutors said. Parts of the bean are highly poisonous and can be used to create ricin.

The Bild newspaper reported that the suspect bought bomb-making material and chemicals used in the production of the ricin.

The daily newspaper wrote that he lived in the Chorweiler neighbourhood of Cologne with his wife and four children.

Ricin has no known antidote and is one of the world's most lethal toxins. It is 6,000 times more powerful than cyanide.

The case comes less than a month after French authorities said they had foiled a terror attack possibly involving the use of ricin. Two brothers of Egyptian origin were arrested.

Germany remains on high alert for jihadist attacks after several assaults claimed by ISIS in the country.

In the worst such attack, Tunisian asylum seeker Anis Amri rammed a truck into crowds at a Berlin Christmas market in December 2016, killing 12.