By Arun Kumar 

Washington, May 18 (IANS) The International Monetary Fund (IMF) chief Dominique Strauss-Kahn is facing growing pressure to quit after US Treasury Secretary Timothy Geithner said the disgraced head was "not in a position to run" the international financial institution.

John Lipsky, second-in-command at the IMF, has taken over as acting chief, but Geithner called on the IMF's executive board to designate an interim head as Lipsky is due to leave the fund later this year. He said the most important thing for the IMF was that it found a leader to fill Strauss-Kahn's shoes after his arrest over an alleged sexual assault on a New York hotel maid Sunday.

"He (Strauss-Kahn) is obviously not in a position to run the IMF and it is important that the board of the IMF formally put in place for an interim period someone to act as managing director," Geithner said addressing the Harvard Club in New York Tuesday.

However, Geithner refused to comment on the case or the details of the charges against Strauss-Kahn.

White House press secretary also declined comment on the case, but maintained "We retain full confidence in the IMF and its continued capacity to fulfill its obligations, to fulfill its role in the global economy during this difficult period."

While he would not "talk about the process for selecting potentially a future head of the IMF," Carney said: "I think the important point is that we believe that the IMF can and will continue to function and fulfill its role in the global economy.

Senate Foreign Relations Committee Chairman John Kerry also stopped short of calling for Strauss-Kahn's resignation, but he called the circumstances of the case "troubling if not damning."

"If the evidence is what it appears to be, I think it would be very difficult for him to manage" as IMF head, Kerry said.

It is the first time top US officials have publicly spoken about the impact of Strauss-Kahn's alleged sexual assault. Washington has a major say in determining who runs the IMF, because it has the largest number of votes in the organisation.

Meanwhile, an IMF spokesman said that diplomatic immunity would not cover its managing director in this case.

"We have not had contact with the managing director since his arrest in New York," he said.