French far-right leader Jean-Marie Le Pen has urged his supporters to boycott the country's presidential run-off election on Sunday.

Le Pen told thousands of supporters at a rally in Paris Tuesday that it would be better not to vote than to back either center-right candidate Nicolas Sarkozy or Socialist Segolene Royal.

Le Pen finished a distant fourth in the first round of voting last month, receiving 3.8 million votes. Analysts say those votes may well determine who wins the French presidency on Sunday.

In Tuesday's comments, Le Pen accused Sarkozy of wooing voters by poaching on Le Pen's own, decades-old plans on immigration and national identity. He said it also would be wrong to vote for Socialist Royal to gain revenge.

Candidate Francois Bayrou, who finished third with 6.8 million votes, did not tell his supporters how to vote in Sunday's run-off poll.

Sarkozy netted more than 31 percent of the vote in the opening round of voting April 22. Royal finished second with nearly 26 percent.

The latest polls show Royal trailing Sarkozy 48 to 52 percent, as the two prepare for a key televised debate Wednesday.

Le Pen startled France in 2002, when he qualified to run against incumbent Jacques Chirac, by finishing second in a first round of voting.

Some information for this report was provided by AFP, AP and Reuters.