CHICAGO | Activists and several Chicago aldermen are investigating dozens of claims that city and county authorities violated immigrant rights, including federal immigration laws affecting jail inmates.

Officials announced Tuesday that the City Council will hear testimony from immigrants next week, a move which advocates have applauded, saying it promotes Chicago's historic reputation as a friendly city for immigrants, officials said Tuesday.

"We understand the value that immigrants hold in our society, whether documented or undocumented," said Chicago Alderman Danny Solis, who is leading the hearings.

Solis and a newly formed commission are looking into at least 30 complaints of racial profiling by Chicago police officers and violations of federal immigration law at Cook County Jail.

The allegations include that undocumented immigrants who have a detainer placed on them by U.S. Immigration and Customs Enforcement are being held longer than a required 48 hours. The time for federal agents to pick them up starts once they've been cleared for release from local law enforcement.

Last month officials at Cook County Jail -- where three ICE agents are stationed each day -- admitted that at least one immigrant inmate was held for ICE longer than 48 hours. Since then, the jail has established several reforms, including a hot line with updated information on the detention status of immigrants held on criminal charges, said Cook County Sheriff's Police spokesman Steve Patterson.

ICE officers who are stationed at the jail pick up about six to eight people each day, said ICE spokeswoman Gail Montenegro.

ICE does not racially profile and does not encourage jails to hold immigrant inmates longer than 48 hours, Montenegro said.

"We are mandated to enforce the nation's immigrations laws and we continue to aggressively do so," she said. "ICE is here and available to work with any law enforcement that requests assistance."

Other allegations made by Chicago aldermen and the group, called the Intergovernmental Commission on Latino Immigrant Rights, involve the Chicago Police Department.

Cook County Commissioner Roberto Maldonado alleges that some officers have pulled over individuals who appear Latino and questioned them their immigration status, which is prohibited by a 2006 Chicago ordinance.

Immigrant rights activists also claim Chicago police officers have reported the immigration status of individuals to ICE.

Chicago police have denied the allegations.

"We do not tolerate racial profiling," said police spokeswoman Monique Bond. "We do not inquire about an individual's immigration status."