CHICAGO — On a day when the authorities here filed murder charges in a case that had come to represent the painful price of gun violence, Mayor Rahm Emanuel on Monday called on state lawmakers to increase minimum sentences for gun crimes in Illinois and require violators to serve the bulk of those prison sentences.

The push to increase minimum sentences for serious gun violations to three years in prison comes as one piece in a larger assortment of efforts — including more mentoring, after-school activities, policing and early childhood education — that Mr. Emanuel and other leaders here say they are advocating to stem gang-connected violence that contributed to more than 500 deaths in Chicago last year.

The legislative proposal came not long before the Chicago police announced arrests in the killing of Hadiya Pendleton, a 15-year-old high school majorette who was fatally shot here a week after taking part in inauguration festivities in Washington. The two men arrested — Michael Ward, 18, and Kenneth Williams, 20 — had ties to a gang, the police said, and one of them had been convicted of a gun charge last year but was granted probation.

The death of Ms. Pendleton, who the police say had no ties to gangs and had once appeared in a video urging young people to stay out of gangs, has drawn new national focus to everyday urban gun violence, beyond the mass shootings that grab national headlines like those at an elementary school in Newtown, Conn., and a movie theater in Aurora, Colo. The two men charged in the case mistakenly thought that Ms. Pendleton and a group of her friends who had gathered in a park on the city’s South Side were members of a rival gang, the police said, and were seeking retaliation for an earlier shooting.