WASHINGTON — At least three employees at U.S. Immigration and Customs Enforcement (ICE) have made serious complaints alleging inappropriate sexual behavior by a senior Obama administration political appointee and longtime aide to Homeland Security Secretary Janet Napolitano, according to court records and a letter describing the claims submitted to a congressional oversight committee.

The complaints are related to a sexual discrimination and retaliation lawsuit filed in May by a senior ICE agent. They accuse Suzanne Barr, the agency's chief of staff, of sexually inappropriate behavior toward employees.

Barr is on leave while the allegations are being investigated, a spokesman for the agency said.

Barr is accused of telling a male subordinate he was "sexy" during an office party and asking a personal question about his anatomy. She is separately accused of offering to perform a sex act with a male subordinate while on business travel in Bogotá, Colombia.

She is also accused of calling a male subordinate from her hotel room and offering to perform a sex act. The names of two of the employees were censored in affidavits reviewed by The Associated Press.

Barr was one of Napolitano's first appointments after she became secretary in 2009.

ICE would not say whether the agency's director, John Morton, witnessed any inappropriate behavior by Barr in the three years he's worked with her.

Two employees came forward with their complaints after New York's most senior ICE agent filed a sexual discrimination and retaliation lawsuit. James T. Hayes Jr., described a "frat house" atmosphere at ICE designed to humiliate male employees under Barr's leadership.

Hayes, who filed the complaint in May, is asking for more than $4 million that would cover compensation he believes he is owed for relocation expenses and financial losses associated with his transfer as well as the full salary and benefits he would have earned until he was eligible to retire.

The Justice Department is seeking to dismiss Hayes' lawsuit on the basis that he did not state a claim for retaliation.

There were 10 sexual harassment claims filed with ICE in 2011, a significant increase over the two cases filed in each of the previous two years, according to equal employment data from the agency. Homeland Security said none of the cases were substantiated.