WASHINGTON (AP) - Barack Obama's aunt, a Kenyan woman who has been quietly living in public housing in Boston, is in the United States illegally after an immigration judge rejected her request for asylum four years ago, The Associated Press has learned.

Zeituni Onyango, 56, referred to as "Aunti Zeituni" in Obama's memoir, was instructed to leave the United States by a U.S. immigration judge who denied her asylum request, a person familiar with the matter told the AP late Friday. This person spoke on condition of anonymity because no one was authorized to discuss Onyango's case.

Information about the deportation case was disclosed and confirmed by two separate sources, one of them a federal law enforcment official. The information they made available is known to officials in the federal government, but the AP could not establish whether anyone at a political level in the Bush administration or in the McCain campaign had been involved in its release.

Onyango's refusal to leave the country would represent an administrative, non-criminal violation of U.S. immigration law, meaning such cases are handled outside the criminal court system. Estimates vary, but many experts believe there are more than 10 million such immigrants in the United States.

The AP could not reach Onyango immediately for comment. No one answered the telephone number listed in her name late Friday. It was unclear why her request for asylum was rejected in 2004.

Onyango is not a relative whom Obama has discussed in campaign appearances and, unlike Obama's father and grandmother, is not someone who has been part of the public discussion about his personal life.

A spokeswoman for U.S. Immigrations and Customs Enforcement, Kelly Nantel, said the government does not comment on an individual's citizenship status or immigration case.

Onyango's case—coming to light just days before the presidential election—led to an unusual nationwide directive within Immigrations and Customs Enforcement requiring any deportations prior to Tuesday's election to be approved at least at the level of ICE regional directors, the U.S. law enforcement official told the AP.

The unusual directive suggests that the Bush administration is sensitive to the political implications of Onyango's case coming to light so close to the election.

Kenya is in eastern Africa between Somalia and Tanzania. The country has been fractured in violence in recent years, including a period of two months of bloodshed after December 2007 that killed 1,500 people.

The disclosure about Onyango came just one day after Obama's presidential campaign confirmed to the Times of London that Onyango, who has lived quietly in public housing in South Boston for five years, was Obama's half aunt on his father's side.

It was not immediately clear how Onyango might have qualified for public housing with a standing deportation order.