French centre-right presidential candidate François Fillon has denounced a left-wing "institutional coup d'etat" as he faces mounting pressure to quit the presidential race, reports the BBC.
He has become mired in a scandal surrounding claims that his Welsh-born wife Penelope was paid large sums over a number of years for "fake jobs".
Far-right rival Marine Le Pen said he had lost voters' confidence.
And there was stinging criticism from his own side too.
One Republican MP, Georges Fenech, said that Mr Fillon's victory in the party's primaries in November had become "obsolete". He said the affair was not just a judicial matter but an ethical and moral one, and an urgent decision had to be made.
Recently the favourite to win the presidency in elections in April and May, he has now slipped behind Ms Le Pen and centrist Emmanuel Macron. Mr Fillon said he would fight the accusations "to the end" on Wednesday but commentators suggested his fate was slipping out of his hands.
Socialist candidate Benoît Hamon ridiculed the idea of a left-wing coup, saying it was "a bit curious to search for plots where there aren't any".