Germany's leading challenger to Chancellor Angela Merkel, lagging badly in the run-up to the Sept. 22 election, rebuked his party's chairman, in another sign of disarray in the Social Democrats' (SPD) campaign.
Peer Steinbrueck told weekly Der Spiegel that he expected all SPD members, including chairman Sigmar Gabriel, to back his election fight, just days after a party meeting in which Gabriel openly criticised Steinbrueck's campaign, the magazine said.
The SPD trail Merkel's conservatives in opinion polls by about 15-16 points. An Emnid poll published on Sunday showed the party slipped a point to 25 percent, its lowest since January, and only 2 points above its poor showing in the 2009 election.
"Only by concentrating all our strengths can the SPD oust this government and Mrs Merkel," Steinbrueck told Der Spiegel.
"I therefore expect that everyone, including the party chairman, will over the next 100 days get behind the chancellor candidate and the campaign in a loyal, constructive manner."
Steinbrueck, a former finance minister, has enjoyed several gaffe-free months, but early campaign mistakes still dog him.
Six days ago, he sacked his chief spokesman, widely blamed for failing to prevent damaging remarks he made - that German chancellors were underpaid and Merkel was so popular because she was a woman - from appearing in a newspaper in December.
The SPD had high hopes of beating Merkel when it chose Steinbrueck last September and both Gabriel and former foreign minister Frank-Walker Steinmeier declined the candidacy. He was seen as an acerbic conservative voice in the left-leaning SPD who could woo less convinced voters away from Merkel.
But his message has been clouded by mistakes. First he got mired in a row over earning 1.25 million euros ($1.7 million) as an after-dinner speaker and he bungled an ensuing public debate.
Despite her strong lead, Merkel may still struggle to form a government if her allies, the liberal Free Democrats, fail to improve on ratings of five percent. She might then be forced to consider a coalition with the SPD like the one she led in 2005-09.