Germany's right-wing populist party Alternative for Germany (AfD) made strong gains in local polls in western states on the back of rising support for its anti-migrant rhetoric, ahead of key state elections this coming weekend.

AfD became the third-biggest party, with support reaching 13.2 percent, in Hesse state, according to initial results released yesterday. The Eurosceptic party, which sparked a storm by suggesting police may have to shoot at migrants seeking to enter Germany, was eroding support for Chancellor Angela Merkel's ruling Christian Democratic Union (CDU) and junior coalition partner Social Democratic Party (SPD).

The result was "very alarming," the vice chairwoman of the SPD's national parliamentary group, Eva Hoegl, told ARD public television on Monday. Manfred Pentz, the CDU's general secretary in Hesse, acknowledged that voters were seeking to punish Merkel and her party over her liberal refugee policies.

Merkel herself had harsh words for the AfD, which she described in an interview with Bild am Sonntag as a "party that does not bring society together and offers no appropriate solutions to problems, but only stokes prejudices and divisions."