Americans have been targeted by what may be an identity-theft scheme in which they're told they are potential jurors and ordered to provide personal information over the phone, U.S. authorities said.

The threat of a fine for shirking jury duty is used to coerce victims into providing confidential data, which could lead to identity theft and fraud, according to the Administrative Office of the U.S. Courts, which provides support services for the federal judiciary.

"These calls are not from real court officials," the office said today in a warning on its Web site. "Federal courts do not require anyone to provide any sensitive information in a telephone call."

Identity theft is one of the most prevalent white-collar crimes, according to U.S. Attorney Paul McNulty of Alexandria, Va., and other federal prosecutors. Almost 10 million Americans, or 4.6 percent of the population, were victims of identity theft in 2002, resulting in losses totaling $52.6 billion, according to the Federal Trade Commission.

In the jury duty scheme, the perpetrators may be identifying potential victims by publicly available court documents, which often include the last four digits of a person's Social Security number for identification purposes, office spokeswoman Karen Redman said.

Most contacts between federal courts and prospective jurors are made by mail, and court officials don't ask for Social Security numbers, credit card numbers or any other sensitive information, the office said in its notice.