It was the latest mob attack to rock Milwaukee in the US midwest and set off another round of civic soul-searching.

"It almost leaves me speechless. It is just a senseless act of violence. It is inhumane. It is embarrassing to the city of Milwaukee and its people. . .

There should be outrage, " said Barbara Nuell-Moore, director of the neighbourhood-improvement group Project Respect.

The 16-year-old girl and a 15-yearold boy have been charged in juvenile court in connection with the attack, which took place on Monday in a house on the city's northside. A 40year-old man who also had sex with the child may also be charged, authorities said. As for the others, "we're dealing with a lot of nicknames so we're trying to track down these people, " said prosecutor Matthew Torbeson.

Numerous violent crimes shocked the Wisconsin city this summer, starting on Memorial Day weekend when 28 people were shot. Homicides are down this year, but two other categories of violent crime are up from 2005 . . . assaults by 22% and robberies by 36%, police say.

According to court papers, the 11year-old girl told police she was interested romantically in the 16-year-old girl, who looked and dressed like a boy.

The alleged victim and two friends went to the 16-year-old's house, where the child performed oral sex on three teenage boys, according to court papers. The 40-year-old uncle of the 16-year-old admitted he also had sex with the 11-year-old and told police that the 16-year-old was directing the child.

The 11-year-old then went to the basement, where there were about 15 males and she told police she "began to choose who she wanted to perform oral sex on, " court papers said.

The 16-year-old told police that the 11-year-old had told her she wanted to perform oral sex on the boys in the house. The 16-year-old denied encouraging her.

The 16-year-old girl and the 15year-old boy were charged with being a party to sexual assault. Torbeson said he will probably seek to have them tried as adults.