The German news outlet, owned by the same parent media company that publishes the nation's third largest newspaper Die Welt, noted that diplomats and emissaries of many nations have been advised to avoid specific restaurants and bars in the so-called European quarter of Brussels.
According to recent estimates from the European External Action Service (EEAS) — the diplomatic arm of the European Union — there are likely "about 250 Chinese and 200 Russian spies in the European capital," cited by Welt.de.
EU diplomats and military attaches have been told to stay away from named cafes and restaurants located within walking distance of the primary European Commission office building, according to reports.
The EEAS additionally asserted that Russian secret agents have historically made up the largest percentage of foreign spies declared to be operating in the Belgian capital, according to Welt am Sonntag.
As well as being the home of the EU, Brussels also claims the honor of being the European headquarters for the North Atlantic Treaty Organization (NATO), leading to memories of a 2003 spy scandal in the city targeting Spanish, British, German and French diplomats who worked within the European Council's Justis Lipsius building.
While those responsible for the notorious bugging scandal were never positively identified, the global intelligence community widely placed the blame on US and Israeli operatives.