While praising German Chancellor Angela Merkel's policies, Bulgarian Prime Minister Boyko Borisov has also shown himself as a practical person ready to make his case outright, a piece in German newspaper Die Welt says.

Citing a recent interview with Frankfurter Allgemeine Zeitung given before Borisov's visit to Berlin, the text [DE] reads: "the Bulgarians bar [the construction of border] fences in the heart of Europe and thus save the Schengen area."

"They don't want to be left abandoned. But the criticism for Berlin is harsh - and unfortunately justified."

This is a reference to comments made by Borisov who has repeatedly urged EU member states to avoid erecting fences between each other, having abandoned himself earlier plans to put up one along the Bulgarian border with Greece.

Hungary has erected such fences along its own borders to curb the inflow of Middle Eastern migrants. 

"What the man from Sofia said must have also resonated during the [conversation] with the Chancellor," `the author, Michael Stürmer, writes. 

"The refugee crisis has an inner side, it is the EU leadership crisis among the governments. The German Question is, undoubtedly and through the rear entrance, again on the stage," he adds in a reference to the old issue of Germany's borders that has had a place in European politics for nearly two centuries, but was deemed to be solved with the reunification in 1990.

The text comes as a rift has been deepening for more than a year between Germany and Central and Eastern European countries over migration policies.