Alan C. Nelson, criticized in a Justice Department audit earlier this year, resigned under fire today as head of the Immigration and Naturalization Service, Atty. Gen. Dick Thornburgh announced.
Deputy INS Commissioner James L. Buck was named acting head of the service.
Justice Department spokesman David Runkel declined to say why Nelson was being replaced before a permanent successor is found.
Department officials have privately expressed dissatisfaction with Nelson, a holdover from the Ronald Reagan Administration.
Gene McNary, the chief executive of St. Louis County, Mo., is expected to be nominated by President Bush to fill the post.
A Justice Department audit ordered by Thornburgh earlier this year criticized the accounting, management and administrative practices at INS. It cited growing backlogs in cases awaiting decisions and the loss by a regional office of 23,000 citizenship certificates.
Nelson defended the agency, criticizing the audit as "grossly deficient," and INS officials in Miami said all but 5% of the citizenship certificates in question had been found.
The audit noted that the agency had spent $1,500 for an oil portrait of Nelson, and Justice Department officials were privately critical of a videotape tribute to Nelson that INS produced at taxpayer expense.