BERLIN, September 28. /TASS/. German secret services have stepped up surveillance of the Russian embassy in Berlin, a move that includes constant, conspicuous helicopter flights over the diplomatic mission's grounds, Bild has reported, citing government sources.

Vans - presumably belonging to German secret services - have repeatedly parked near the embassy for several days. The aim of this conspicuous action is to increase pressure on Russian embassy staff, the newspaper writes.

Furthermore, according to the publication, German authorities intend to tighten scrutiny of Russian businesspeople and their family members who hold German visas. Upon entry, they will face "uncomfortable questions" at the border, including inquiries regarding the purpose of their visit to Germany and their activities within the country.

Earlier, Russian ambassador to Germany Sergey Nechayev stated that Russia had done nothing to harm Germany and had always sought common ground with sensible German politicians. The bilateral relationship has never faced such a serious situation in the post-war era.