Explosion rocks Harvard medical building as suspects flee scene. Boston arson unit investigating intentional blast on fourth floor of Longwood medical campus. No injuries reported.

A fire and explosion at a convenience store in northern Mexico on Saturday killed at least 23 people, including children, and injured 12 others, local officials said. The fire occurred in downtown Hermosillo, the capital of Sonora state, Gov. Alfonso Durazo said in a video posted on social media.