PHILADELPHIA (AP) — Police in Philadelphia say a 3-year-old is in critical condition after being shot in the head by his 6-year-old brother.

Authorities say the younger boy suffered a gunshot wound to the left side of his forehead just after 3 p.m. Saturday. The two boys were on the second floor of their north Philadelphia home when the shooting happened.

The injured boy was taken to Temple University Hospital.

Investigators tell WPVI-TV in Philadelphia that they believe a 12-year-old brother also was at home, but no adults.