BERLIN, March 21 (Xinhua) -- German police have significantly expanded the use of controversial facial recognition software, the newspaper "Rheinische Post" reported on Wednesday.

"Rheinische Post" hereby cited an official response by the interior ministry to a Left party (Linke) parliamentary enquiry.

According to the document, the use of facial recognition software by the Federal Criminal Police Office (BKA) and state criminal investigation offices (LKAs) rose from 1,673 instances in 2010 to 27,436 instances in 2017.

In total, BKA and LKA security authorities have now recorded 115,798 facial recognition investigations since 2008. The news of growing instances in the use of the controversial surveillance technology comes before the completion of an ongoing 12-month facial recognition pilot project at a Berlin railway station which has been criticized heavily by data protection organizations.

Speaking to "Rheinische Post" on Wednesday, Andrej Hunko, the Left party's Europe spokesperson, described the development as a "significant threat to data protection and the principle of data minimization." Asylum seekers, in particular, were becoming "guinea pigs for a surveillance state".

Back in December 2017, former interior minister Thomas de Maiziere announced that the facial recognition software would be introduced in all German railway stations and airports if the Berlin surveillance test proved successful. Security authorities have justified the unusual measures as offering an effective means to prevent terrorist attacks.

Nevertheless, the German Bar Association (DAV) has criticized the absence of an adequate legal foundation for the widening of facial recognition by police. DAV has argued that the indiscriminate mass-scanning of citizens' faces at airports and railways would constitute a severe breach of their constitutional right to privacy.?