WATERLOO (AP) - Immigration rights activists are concerned that the federal government may be planning an immigration raid on workers in Waterloo similar to one carried out in Marshalltown in 2006.

Several activists gathered on Sunday at a Waterloo church and at the home of a local social worker to discuss what they consider to be an impending raid.

Discussions were prompted by an announcement last week that federal officials have leased the National Cattle Congress fairgrounds in Waterloo.

Immigration activists say they fear the fairgrounds is being prepared as a detention center.

Federal officials have refused to comment on whether they're planning an immigration raid.

The activists are discussing strategies for caring for children and identifying detainees after a raid.

Sol Varisco-Santini of Catholic Charities in Des Moines says the stress level is high.

An information session held at the Queen of Peace Catholic Church after a noon mass in Spanish, included several handouts that detail what people should do when confronted by police, and provided contact information for immigration attorneys in Iowa.

In December 2006, immigration officials raided the Swift & Co. meatpacking plant in Marshalltown. Several workers were taken to Camp Dodge in Johnston and held in military barracks.

Tyson Foods Inc. owns a meatpacking plant in Waterloo.