Nancy Arseno discusses the arrest of her husband, Mario, in an operation conducted by U.S. Immigration and Customs Enforcement officers. Arseno is surrounded by her children, clockwise from the left, Alex, 7; Shannon, 10; Timmothy, 8; Jessica, 2; and Emily, 4. Photo by John Gurzinski.

A six-day operation has led to the arrests of 179 "immigration violators" in Clark County, federal officials announced Thursday, and most of the people arrested already have been removed from the country.

U.S. Immigration and Customs Enforcement officers from three states made the arrests in what officials described as the largest ever local operation targeting illegal immigrants who have failed to comply with deportation orders.

"Taking immigrant fugitives off our streets is a top ICE priority," said John Torres, acting director of the agency's office of detention and removal.

Vicenta Montoya, an immigration attorney who represents several illegal immigrants who were arrested during the operation, accused officials of planning the sweep in response to recent demonstrations by large groups of immigrants and in response to proposed legislation that would provide a path to citizenship for millions of illegal immigrants in the United States.

She also accused immigration officials of trying to "intimidate the undocumented community."

Torres said the Clark County operation, which ended Wednesday, was part of a national program that became operational when ICE was established in March 2003. A similar operation resulted in 34 arrests in the Las Vegas area in 2004.

Mark Edwards, founder of the Wake Up America Foundation, applauded the effort that led to the recent arrests but said, "I'm wary of it that it's just for show.

"It's just the tip of the iceberg when they do something like that," said Edwards, whose group opposes illegal immigration.

Torres said as many as 3,000 "fugitive aliens" are using Las Vegas addresses. Fugitive aliens are those who have been ordered deported by an immigration judge but failed to comply with the order.

"They've had their day in court," Torres said.

Officials estimate that more than 500,000 fugitive aliens live in the United States.

Of the immigrants taken into custody during the Clark County sweep, dubbed Operation City Lights, more than 130 had been removed from the United States as of Thursday, Torres said.

He said most of the people arrested had outstanding orders of deportation. The others were illegal immigrants discovered in the process of targeting the fugitives.

Jamie Zuieback, an ICE spokeswoman, said the agency engages in "targeted enforcement actions" based on leads.

"We don't conduct random sweeps," she said.

Of those arrested during the operation, Torres said, 18 had criminal records. Among those arrested was Nery De Leon, a 31-year-old Guatemalan national who was sentenced to four years in prison in California during the early 1990s for transporting drugs.

The majority of those arrested during the operation are Mexican nationals, but the group also included immigration violators from Iraq, Egypt, Peru, the Philippines, Samoa and El Salvador.

Fugitive operations teams from Los Angeles and Phoenix traveled to Las Vegas to work with local officers on the enforcement effort.

Since the beginning of October, fugitive operations teams have made more than 12,000 arrests nationwide. The four fugitive operations teams responsible for covering the Los Angeles and Las Vegas areas have made more than 2,000 arrests during that time.

ICE has 38 fugitive operations teams nationwide and expects to have 52 by the end of the year, Torres said.

"This operation definitely demonstrated to us that there was a need to have a team in this area," he said.

Torres said plans are in place for Las Vegas to have its own fugitive team by 2007.