MARIGNANE, France (CNN) -- A personal rivalry between two leaders of France's far-right movement went a step further Sunday when opponents of party founder Jean-Marie Le Pen elected Bruno Megret to head a splinter group.

The vote came during a two-day conference in southern France held by rebel members of the National Front. Le Pen has said the meeting is illegal, calling it a "putsch" against him.

The 2,300 delegates to the congress in Marignane named Le Pen "honorary president" of their new National Front-National Movement, an action rejected by the 70-year-old Le Pen.

Megret, 21 years younger than his former mentor, claimed he had effectively seized control of the party and rejected Le Pen's claims that he was a traitor to the party.

"We are neither putschists nor mutineers nor pirates," he said, "and the National Front is not the Bounty."

Both factions of Western Europe's largest extreme-right party plan to field slates for the June 13 European parliament elections, and both sides claim they will win out in the end.

The feud between Megret and Le Pen began last summer when Le Pen suggested that his wife replace him as party head when it appeared he would be convicted of assault and barred from holding or running for office. Le Pen was convicted, but has appealed and is considered likely to avoid the ban.

Megret, a former National Front deputy in parliament, openly criticized Le Pen's position. The schism deepened until December, when Le Pen kept Megret and his followers from party leadership roles. That move prompted the Marignane congress.

Recent polls show Le Pen, who founded the party in 1972, holding on to the support of most National Front members, while other polls say that the mainstream right will benefit from the split.

Le Pen is known for blustery, Nazi-styled theatrics in front of a crowd, while Megret is a quieter man who prefers working behind the scenes to enflaming emotions.

Reuters contributed to this report.