A 13-year-old and 15-year-old were both charged with the murder of a Chicago store clerk who was killed during a shootout with a group of robbery suspects Friday afternoon, police said.

Four suspects entered the store about 1:45 p.m. in the first block of East 71st Street in the Park Manor neighborhood on the city's South Side and took cash from the register by force, Chicago police said.

As the clerk, later identified by the Cook County medical examiner's office as Mohammed I. Maali, took out his own gun and fired shots, the robbers returned fire and struck the clerk in the chest, police said.

Maali, 33, was taken to the University of Chicago Medical Center where he was later pronounced dead, police said.

Police confirmed Friday that four suspects had been arrested, but only announced charges against two Saturday evening.