BERLIN (AP) – German authorities say they have arrested a Russian national suspected of plotting an Islamic extremist attack in Germany along with an alleged accomplice detained last year in France.

Federal prosecutors said the 31-year-old, identified only as Magomed-Ali C., was arrested Wednesday in Berlin. They said that, in Oct. 2016, he stored a “significant quantity” of the explosive TATP at his apartment for an attack in Germany – time and place unknown.

However, prosecutors say that the plans by C. and alleged accomplice Clement B. were disrupted by a “preventive police measure,” and they decided to split up. Clement B. left for France, and was arrested in Marseille in April 2017 over plans to carry out an attack in France. The French investigation produced evidence against Magomed-Ali C.