A health official says the death toll from a day care center fire in northern Mexico has risen to 46 following the death of a toddler.

Sonora state Health Secretary Raymundo Lopez Vocovich says the 3-year-old boy died Friday at a hospital in the central city of Guadalajara.

Lopez Vocovich said Saturday that 20 children and five adults remain hospitalized, including six children who have been sent to U.S. hospitals.

Officials say last week's fire started at an adjacent warehouse and may have been caused by a short circuit or overheating in the building's air conditioning system. The blaze spread to the day care center's roof, sending fire raining down on the children and teachers.

Thirty babies and toddlers died on the day of the fire.