Until now, a possible tie-up between any of Germany's mainstream parties and the rising nationalist, Eurosceptic Alternative for Germany (AfD) party has always been strictly seen as a political taboo.

What was previously unthinkable could eventually become a reality however as Angela Merkel's embattled center-right Christian Democratic Union (CDU) party feels compelled to consider other power-sharing options.

One possibility is an alliance with the anti-mass immigration AfD, on the regional level at least.

Local elections in three states in the east of the country where polls suggest that the AfD could become the strongest political force - Saxony, Brandenburg and Thuringia - is forcing the CDU to re-think its stance. "We should not rule out a coalition" with the AfD, Ulrich Thomas, one of the regional leaders of the CDU in the central state of Saxony-Anhalt, told local daily Mitteldeutsche Zeitung.

Saxony-Anhalt will elect a new regional parliament in 2021 and another local CDU leader, Lars-Joern Zimmer, pointed out that voters of his party and the AfD often held similar views and felt themselves to be part of Germany's "conservative majority". Recently, Germany's former domestic spy chief and a member of the CDU's right-wing, Hans-Georg Maaßen, also refused to rule out an alliance on the national level, saying "you never know".

Deputy chief of the AfD, Georg Pazderski, suggested that "the united front (against his party) is beginning to crumble. In particular, the CDU base - which has been massively disappointed by its own leaders - cannot be told that the party should be closer to the left than to AfD," he told the Sunday edition of Welt newspaper.