French financial prosecutors have decided to continue their investigation into embezzlement allegations against conservative presidential candidate Francois Fillon, saying they have too much evidence to drop the case.

Mr Fillon's team said he will maintain his campaign pending further investigation, which centres on claims that his wife Penelope, from Abergavenny in Wales, and two of his children earned as much as one million euro (£850,000) for fake parliamentary jobs.

Mr Fillon has denied wrongdoing.

France's already unpredictable presidential campaign plunged into new uncertainty when the national financial prosecutor's office opened a preliminary investigation last month into embezzlement and misappropriation of public funds, after newspaper Le Canard Enchaine first reported about the parliamentary jobs.

The prosecutor's office said it received the initial police report into the case on Wednesday and has decided to continue investigating.

"The numerous elements gathered already do not allow us to envisage dropping the case in its current state," the prosecutor said in a statement. "The investigations will continue."

Polls considered Mr Fillon the front-runner for the April 23-May 7 election before the scandal erupted.

Centrist Emmanuel Macron and nationalist Marine Le Pen have seen their poll numbers rise since then.

Mr Fillon initially said he would step down from the race if he was given charges, but has recently appeared determined to continue his campaign despite the scandal.

His lawyers said the prosecutor's decision was "without justification" and accused the prosecutors of violating rules about investigative secrecy.

While it is not illegal for politicians in France to employ family members, many voters were shocked by allegations that the Fillon family's jobs were fake - and by the large sums they were paid.

Mr Fillon won the conservative primary on his reputation as an unsullied politician and his promises to slash public spending.

The prosecutor has not yet taken the case to the next level, a judicial inquiry, which would allow for preliminary charges.

A judicial official stressed that prosecutors only have the initial police report and cannot make a decision on next steps until the final police report is submitted in the coming weeks.