Federal officials say only six illegal immigrants volunteered to leave the United States in the first week of a pilot program inviting nearly a half-million people to self-deport.

The U.S. Immigration and Customs Enforcement program is aimed at more than 450,000 illegal immigrants who have received but ignored court orders to leave the country and who also have no criminal records.

It is available in just five cities, including Phoenix, where an Estonian was among the six who signed up by Wednesday.

Officials say the program offers a less disruptive option than arrest and instant jailing by immigration agents who track down immigration fugitives at their homes or workplaces.

It gives those who participate up to three months to wrap up their personal affairs.

The other cities in the program are Santa Ana, Calif., San Diego, Chicago, and Charlotte, N.C. An Indian husband and wife and a Guatemalan signed up in Chicago, a Salvadoran volunteered in Charlotte and a Mexican in San Diego.