Dominique Strauss-Kahn this morning gave in to mounting pressure following his arrest for an alleged sexual assault by resigning from the IMF.
Strauss-Kahn, who has steered the IMF through one of the toughest financial crises in living memory, told the organisation's executive board he would be resigning as managing director with immediate effect.
In a statement he said: "It is with infinite sadness I feel compelled today to present to the executive board my resignation from my post of managing director of the IMF."
Strauss-Kahn, who is being held in jail in New York after being refused bail, faces a number of charges relating to the alleged sexual assault of a 32-year-old maid in a New York hotel last Saturday.
On Monday a judge in New York denied Strauss-Kahn bail - despite the offer of a $1m (£618,000) guarantee - saying there was a risk the IMF chief would flee the country.
Pressure had been building on Strauss-Kahn to step down from the IMF since the charges emerged, with US Treasury Secretary Tim Geithner warning on Tuesday night he could not continue in the role.
In his letter to the board, Strauss-Kahn said the IMF had achieved "great things" during the financial crisis, and he also strongly denied the claims made against him.
"To all, I want to say that I deny with the greatest possible firmness all of the allegations that have been made against me," he said.
"I want to protect this institution which I have served with honour and devotion, and especially—especially—I want to devote all my strength, all my time, and all my energy to proving my innocence."
John Lipsky, who has acted as second in charge since Strauss-Kahn's arrest, will remain acting managing director until a new appointment is made.
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