Security authorities in Germany uncovered a cache of handguns in a forest near the capital Berlin last year, which they believe was intended to be used to carry out assassinations on behalf of Russia, according to reports on Friday.

The daily Süddeutsche Zeitung and public broadcasters NDR and WDR reported earlier Friday that one suspect was arrested in Romania.

Interior Minister Alexander Dobrindt said German authorities were in touch with their Romanian counterparts about the suspect's potential extradition.

"This case demonstrates that we are ​operating under a high threat level," ​Dobrindt told a press ​conference.

What else did Dobrindt say about the weapons stash?