France faces a week of political uncertainty with Francois Fillon, the right wing presidential candidate, under mounting pressure to quit the race because of a fake-jobs-for-the-family scandal and divisions over whether, and how, to replace him.

As Fillon's two closest rivals, the far-right's Marine Le Pen and independent Emmanuel Macron, began vigorously campaigning, the former prime minister appeared to believe he could ride out the storm engulfing his faltering campaign.

Fillon said he would fight to the end to defend his position as the party's nominee. A source in his camp said he would likely reinforce that message on Monday.