German police have arrested a 32-year-old Iranian man on suspicion of planning an attack using deadly chemicals, officials said Sunday.

Police and prosecutors said the man and another person were detained overnight in the town of Castrop-Rauxel, northwest of Dortmund.

In a joint statement, they said the man is suspected to have planned a serious terrorist attack, for which he had allegedly sought to obtain the potent toxins cyanide and ricin.

Specialists wearing anti-contamination suits were seen carrying evidence out of the man's home.

A spokesman for Duesseldorf prosecutors later said an initial search of the premises turned up no toxic substances, the Deutsche Presse-Agentur (dpa) reported.

It wasn't immediately clear how far advanced the plans for an attack were and whether the suspect had picked a specific target.

Dpa quoted the top security official for North Rhine-Westphalia state, Herbert Reul, as saying authorities had received "a serious tip that led police to intervene the same night."

Tabloid newspaper Bild reported that the tip about the alleged plot came from an allied intelligence agency.

Dpa cited an unnamed German security official saying there was no indication the suspect had acted on behalf of the Iranian state, but rather that he allegedly a terrorist group.

Five years ago, German police arrested a Tunisian man and his wife on suspicion of planning to carry out a ricin attack in the name of the Daesh terrorist group.

They were later found guilty and sentenced to 10 and eight years of imprisonment, respectively.

Even small amounts of ricin, which is produced from the seeds of castor oil plants, can kill an adult if eaten, injected, or inhaled.