PARIS (AFP) - French Prime Minister Manuel Valls will on Monday (Dec 5) announce he is running to become the Socialist candidate for president in elections next year, sources close to him have told AFP.

The Prime Minister's office announced only that he would make a statement at 6.30pm (1.30am Singapore time) from his political base in Evry, south of Paris.

But his entourage confirmed that he would put an end to the speculation over whether he would run - seen as highly likely following President Francois Hollande's decision on Thursday not to stand.

The French left, in search of a new leader after Mr Hollande's exit, will hold a US-style primary in January to choose a presidential candidate.

The first round of the presidential election in France is due to be held on April 23 with a decisive run-off on May 7.

Polls show the far-right Marine Le Pen could triumph in the first round but would likely lose to the right-wing candidate Francois Fillon in the run-off.

The divided left is in disarray with former economy minister Emmanuel Macron also throwing his hat into the ring as an independent.

If Mr Valls does announce a run for the Elysee presidential office, he will have to resign as prime minister, sparking a government reshuffle.