NEW YORK - Dominique Strauss-Kahn, a wealthy French politician accustomed to high living and globe-trotting, wants off Rikers Island, known as one of America's largest and roughest jail complexes.

Behind bars on Rikers since Monday, the beleaguered IMF chief is scheduled to return to a Manhattan court Thursday afternoon to again ask for bail on charges he sexually assaulted a hotel maid. The move seems certain to face vigorous opposition by prosecutors.

Late Wednesday, Strauss-Kahn resigned as managing director of the International Monetary Fund, according to a letter released by its executive board.

In the letter, Strauss-Kahn denied the allegations but said he felt compelled to resign with "great sadness" because he was thinking of his family and also wanted to protect the IMF.

In court papers filed by his defense team Wednesday, Strauss-Kahn said he had surrendered his passport and wouldn't flee the country. His attorneys proposed posting $1 million cash bail and confining him to the home of his daughter, Camille, a Columbia University graduate student, 24 hours a day with electronic monitoring.

Strauss-Kahn, 62, "is a loving husband and father, and a highly regarded diplomat, politician, lawyer, politician, economist and professor, with no criminal record," his attorneys wrote.

Special coverage:  IMF chief's Sex Scandal

They had proposed similar conditions at an earlier bail hearing but added the promise of house arrest Wednesday. A judge denied him bail Monday.

Investigators have revisited the penthouse hotel room to cut out a piece of carpet in a painstaking search for DNA evidence, law enforcement officials said Wednesday.

New York detectives and prosecutors believe the carpet in the hotel room may contain Strauss-Kahn's semen, spat out after an episode of forced oral sex, the officials told The Associated Press.

One of the officials said that the DNA testing was being "fast-tracked" but that the results could still be a few days away.

The two officials spoke to the AP on condition of anonymity because neither was authorized to speak about the case publicly and because it has gone to a grand jury.

The maid, a 32-year-old immigrant from the West African nation of Guinea, told police that Strauss-Kahn came out of the bathroom naked, chased her down, forced her to perform oral sex on him and tried to remove her underwear before she broke free and fled the room.

The AP does not identify alleged victims of sex crimes unless they agree to it.

Strauss-Kahn went from his $3,000-a-night hotel suite to an isolated cell block at Rikers normally reserved for patients with contagious diseases. Kept in protective custody and on a suicide watch, authorities said he ate his meals alone in a single cell and was escorted everywhere by prison guards.

Defense lawyers can raise the issue of bail as many times as they like, and it's common to make new proposals and try again after a client gets high or no bail, said Stuart P. Slotnick, a New York defense lawyer not involved in the case. Such attempts can succeed if a judge is persuaded that new information reduces the perceived risk that the person won't come back to court if released.

Living elsewhere is often seen as raising that risk, but it's not insurmountable, Slotnick said.

In a case like Strauss-Kahn's, bail "is not going to be a slam dunk, but if they can convince the judge that he's not a risk of flight, that he's going to come back, then he'll get bail," Slotnick said.

Manhattan prosecutors didn't immediately comment on the new bail motion.

Another hearing had been scheduled for Friday, the deadline for prosecutors to bring an indictment, agree to a preliminary hearing or release him.

In addition to examining the Sofitel Hotel suite for further potential DNA evidence, investigators were looking at the maid's keycard to determine whether she used it to enter the room, and how long she was there, officials said.

Police Commissioner Raymond Kelly declined to comment Wednesday on the details of the evidence-gathering but said results of any DNA and other testing have not yet come back. He said the detectives investigating the case found the maid's story believable.

"Obviously, the credibility of the complainant is a factor in cases of this nature," Kelly said. "One of the things they're trained to look for, and what was reported to me early on, was that the complainant was credible."

One of Strauss-Kahn's attorneys, Benjamin Brafman, said at his client's arraignment this week that the forensic evidence "will not be consistent with a forcible encounter." That led to speculation the defense would argue it was consensual sex.

The woman's lawyer, Jeffrey Shapiro, has dismissed suggestions from some of Strauss-Kahn's defenders that she made up the charges or tried to cover up a consensual encounter.

Strauss-Kahn is one of France's highest-profile politicians and was seen as a potential candidate for president in next year's elections. His arrest shocked France.

The scandal comes at a critical moment for the International Monetary Fund, which is trying to shore up teetering economies in Europe. The IMF is an immensely powerful agency that loans money to countries to stabilize the world economy. In exchange it often imposes strict austerity measures.