MAGDEBURG, Germany (Reuters) - Thousands took to the streets to protest against the far-right Alternative for Germany (AfD) on Friday and Saturday as the party held a convention to choose its candidates for European parliamentary elections next year.

Protesters outside the conference venue in the city of Magdeburg waved banners with messages like "stand together against right-wing hate" or "Nazis out".

Polling at 22% behind the opposition conservatives, the AfD denies it is a Nazi party. Analysts say it is tapping into voters' fears about recession, migration and the green transition.

The AfD last month won a vote for a district leader for the first time and is on course to win three upcoming state elections in east Germany. Its rise has drawn concern from the domestic intelligence service about extremism.

"Germany has understood that the right is the future," AfD's leader Alice Weidel told Italian newspaper La Repubblica on Saturday. "The voices are getting louder."

The AfD says its vision of Europe is "one of sovereign nation states instead of an EU superstate" and it wants "free citizens instead of paternalism and bureaucratic control."

But any temptation for the mainstream to join hands with the far-right can backfire.

Germany's main opposition leader Friedrich Merz was on Monday forced to row back from comments suggesting he could work with the AfD at a local level.

Merz, who leads the Christian Democrats (CDU), hurriedly ruled out cooperation of any kind with the AfD after a backlash from within his own ranks.

Vocal among the protesters in Magdeburg were "Grannies against the far-right" calling for an end to racism and far-right politics.

(Reporting by Maria Martinez and Oliver Denzer; Additional reporting by Alvise Armellini; Editing by Giles Elgood)