The leader of the International Monetary Fund, a possible candidate for president of France, was yanked from an airplane moments before it was to depart for Paris and arrested in the alleged sexual assault of a hotel maid, police said.

Dominique Strauss-Kahn, 62, was arrested on charges of a criminal sex act, attempted rape and unlawful imprisonment. He had been taken off the Air France flight at John F. Kennedy International Airport on Saturday afternoon by police officers.

Strauss-Kahn's lawyer, Benjamin Brafman, told The Associated Press that his client will plead not guilty at his expected Sunday afternoon arraignment.

"He denies all the charges against him," Brafman said. "And that's all I can really say right now."

France woke to the news Sunday with a measure of surprise.

Strauss-Kahn was expected to be the main challenger against President Nicolas Sarkozy, whose political fortunes have been flagging, in next year's presidential elections. The arrest could shake up the race and throw the long-divided Socialists back into disarray about who they could present as Sarkozy's opponent.