Federal investigators are looking to freeze the assets of Ruth Madoff, the wife of jailed swindler Bernard Madoff, because of fears she might flee the country or otherwise spirit away some of the $93 million in her name, the New York Post reported on Sunday, citing sources.

The report said the Securities and Exchange Commission and federal prosecutors in Manhattan are preparing to ask a judge to formally freeze Ruth Madoff's assets as soon as possible.

An SEC source told the Post that U.S. attorneys will ask for the freeze in the next week or so. They will argue the assets are derived from ill-gotten gains, according to that source.

Bernard Madoff, 70, was jailed on Thursday after pleading guilty to running the biggest investment fraud in Wall Street history that drew in as much as $65 billion over 20 years.

His sentencing on 11 criminal charges is scheduled for June 16, when he could be imprisoned for the rest of his life.

Married to Bernard Madoff for nearly 50 years, Ruth Madoff played no formal role at her husband's company and has not been accused of any wrongdoing.

Still, Ruth Madoff has gotten her share of attention in the case for activities including mailing more than $1 million worth of jewelry and watches in violation of a court order, withdrawing $15.5 million before her husband's December 11 arrest and an attempt to separate millions of dollars of her assets from his purported fraud.

She has agreed to a voluntary asset freeze, but the Post says that agreement is not legally binding.

Ruth Madoff's attorney Peter Chavkin could not be immediately reached for comment.

(Reporting by Michael Erman)