SALT LAKE CITY -- A list containing the names and personal information of 1,300 people who an anonymous group contends are illegal immigrants has been mailed around Utah, terrifying the state's Hispanic community.

Republican Gov. Gary Herbert wrote in a tweet Tuesday that he has asked state agencies to investigate the dissemination of the list -- sent anonymously to several media outlets, and law enforcement and state agencies. A letter accompanying the list demands that those on it be deported immediately.

Most of the names on the list are of Hispanic origin. The list also contains highly detailed personal information such as Social Security numbers, birth dates, workplaces, addresses and phone numbers. Names of children are included, along with due dates of pregnant women on the list.

"My phone has been ringing nonstop since this morning with people finding out they're on the list," said Tony Yapias, former director of the Utah Office of Hispanic Affairs. "They're feeling terrorized. They're very scared."

The list's release comes as several conservative Utah lawmakers consider sponsoring a tough new illegal immigration law similar to the one passed recently in Arizona.

Arizona's law, which takes effect July 29, directs police enforcing other laws to ask about a suspect's immigration status if there is reason to believe the person is in the United States illegally.

The Obama administration sued Arizona last week to prevent the law from taking effect, arguing that the state is impinging on federal responsibilities for dealing with immigration.

Herbert has said a new immigration law likely will be passed when lawmakers convene in January, although he said it may be different from Arizona's. Herbert spokeswoman Angie Welling was traveling back from Washington, D.C., Tuesday and could not immediately be reached for comment.

The letter included a long recipient list, including newspapers, broadcast outlets, The Associated Press, law enforcement and state agencies, various Utah officials, and the Department of Homeland Security. The letters began arriving in mailboxes in recent days.

Dave Lewis, communication director for the state Department of Workforce Services, said his agency didn't receive a copy of the list from the governor's office until late Tuesday.

"We've got some people in our technology department looking at it right now," he said. "It's a high priority. We want to figure out the how's and why's."

He said his agency is one of several with access to the information included in the list.

The letter says some names on the list were sent to the Immigration and Customs Enforcement office in Salt Lake City in April. It says the new list includes new names, for a total of more than 1,300.

Included with the new letter is one dated April 4 addressed to "Customs and Immigration" and from "Concerned Citizens of the United States."

In the April letter, the writers say their group "observes these individuals in our neighborhoods, driving on our streets, working in our stores, attending our schools and entering our public welfare buildings."

"We then spend the time and effort needed to gather information along with legal Mexican nationals who infiltrate their social networks and help us obtain the necessary information we need to add them to our list," the letter says.

Agency spokeswoman Virginia Kice said ICE received a copy of the list, but she declined to say whether it is investigating the immigration status of the people on it.

"As a matter of policy, we don't confirm we are investigating an allegation or possible violation unless the inquiry results in some type of public enforcement action," Kice said.

She noted that because ICE has finite resources, it focuses its efforts "first on those dangerous convicted criminal aliens who present the greatest risk to the security of our communities, not sweeps or raids to target undocumented immigrants indiscriminately."

Kice added that the agency has had a means for the public to report suspected criminal activity for several years -- a 24-hour tip line staffed by trained enforcement personnel.