Pranksters posing as a delivery service won a contract from the far-right Alternative for Germany (AfD) to distribute a million campaign flyers - instead sending the leaflets back to the party's offices two days before Sunday's election.
The AfD, which polls show with support of about 11%, said the "fraudulent operation" appeared to have been carried out by members of a Berlin-based art group called the Centre for Political Beauty.
"The flyers are now useless for our campaign," AfD co-chief Tino Chrupalla said in a statement. "This is precisely the goal of those behind this operation ... They are trying to intentionally harm the AfD in the election."
The Centre for Political Beauty did not immediately respond to an emailed request for comment.
Four years ago, the art group built a pared-down version of Berlin's Holocaust memorial near the home of an AfD politician who sparked outrage by suggesting history books should be more focused on German World War Two victims.
The AfD entered Germany's parliament in 2017, drawing support from voters angry at Chancellor Angela Merkel's decision in 2015 to welcome almost one million asylum seekers, mainly from Syria, Iraq and Afghanistan.
Merkel's conservatives are almost neck-and-neck in opinion polls with the centre-left Social Democrats, who have a narrow lead.
The AfD, which is ostracised by all political parties, denies holding racist views.
(Reporting by Joseph Nasr; Editing by Helen Popper)
