A 15-year-old girl who had performed at US President Barack Obama's inauguration festivities is the latest victim of the ever-increasing homicide toll in the president's hometown, killed in a Chicago park as she talked with friends by a gunman who apparently was not even aiming at her.

Chicago police said Hadiya Pendleton was in a park about 2 km from Obama's home in a South Side neighborhood on Tuesday afternoon when a man opened fire on the group. Hadiya was shot in the back as she tried to escape.

The killing comes at a time when Obama, spurred by the Connecticut elementary school massacre in December, is actively pushing for tougher gun laws.