PARIS (Reuters) - French far-right leader Marine Le Pen on Thursday lashed out at what she called "undemocratic" behavior by mainstream parties after polls showed tactical voting could keep her party out of power in key regions.
The Front came first nationally in the regional elections' first round on Dec. 6 and led in six regions out of 13, including the north where Le Pen is standing and the southeast, where her niece Marion Marechal-Le Pen is the lead candidate.
Since then, however, the third-placed Socialist Party has pulled out of the race in both those key regions, urging its supporters to back Nicolas Sarkozy's Republicans in the run-offs on Dec.13 to keep the Front out of power.
Opinion polls on Wednesday and Thursday in three of regions targeted by the Front showed voters heeding the Socialist call to vote for the conservatives, although in two regions the outcome was within the margin of error.
"They can do nothing against the survival instinct of the people," Le Pen said, urging supporters to vote massively in Sunday's decisive second round vote to counter what she called a "state defamation campaign ... unworthy of a modern democracy".
To the cheers of supporters waving French flags and shouting "Marine president" at a campaign rally, Le Pen mocked what she called "panicked (mainstream) politicians."
"Do not doubt and do not give up," she said. "They are only strengthening our determination."
Le Pen topped the first round in Nord-Pas-de-Calais-Picardie region with over 40 percent of the votes. Her niece Marion Marechal-Le Pen did the same in Provence-Alpes-Cote d'Azur (PACA) in the south-east.
Fears over immigration, the Islamic State attacks in Paris that killed 130 people last month, disaffection with mainstream politics and frustration at high unemployment were among factors behind the party's best performance in its history.
In the north, Le Pen would win 47 percent of the vote while Xavier Bertrand, a former minister with the conservative Republicans, would get 53 percent, the TNS Sofres-OnePoint poll showed.
In the southeast, Marechal-Le Pen would get 46 percent against 54 percent for Christian Estrosi, the conservative mayor of the Riviera city of Nice.
But on Thursday another poll in the southeast, this one by Harris Interactive, showed a much smaller lead for Estrosi, with 51 percent of the votes against 49 percent for Marechal-Le Pen.
Another of the six regions where the FN led in the first round was Alsace-Champagne-Ardenne-Lorraine in the east, where it won 36 percent of the vote.
There, the Socialist lead candidate Jean-Pierre Masseret resisted his party's call to step down, making the outcome of the three-way vote uncertain.
A survey by Elabe pollsters showed the conservative candidate attracting 43 percent of the vote in that region, slightly ahead of the Front's number 2 official Florian Philippot, who would get 41 percent. The difference between the two was within the margin of error.
The FN also came first on Dec.6 in the central regions of Bourgogne-Franche-Comte, Centre-Val de Loire and in the southern region of Languedoc-Roussillon-Midi-Pyrenees, with just under a third of the vote in each.
The regional vote is the first since a reform that redrew boundaries to create 13 larger regions from 22 smaller ones before. The Socialist Party, which runs a deeply unpopular national government under President Francois Hollande, looks set to lose the domination of the regions it won in 2010.
The first round poll put the Socialists ahead in only two regions and Sarkozy's Republicans ahead in four. The Republicans have decided not to follow the Socialists' example of pulling out in regions where they are third-placed.
Additional reporting by John Irish; Editing by Tom Heneghan