VIDEO: Chicago's Top Cop Explains Rising Murder Rate

The rash of shootings and spike in murders in Chicago this year can be attributed to the city's 59 gangs and more than 600 gang sets, Police Superintendant Garry McCarthy told CBS News.

Through June 11, 228 people had been slain, up 35% from 169 in the same period last year. There have been 976 shootings, up 11% from 881 in the same period a year earlier, the department said.

McCarthy added that there had been a 17% drop in homicides in the past month.

The city's murder rate is now "three times the murder rate of New York City," said McCarthy, who added that his goal is to "get to zero."

The department plans to pay officers overtime to work summer weekends to combat the violence, reports the Chicago Tribune.