Mexican authorities say two university professors have been injured by the explosion of a package bomb on a campus near the national capital.
The prosecutor's office for the state of Mexico says a messenger service delivered the package Monday to the cubicle of one of the victims at a campus of Monterrey Technological Institute.
Prosecutor's spokesman Alfredo Albiter says investigators are trying to determine whether the bomb was detonated with a timer or by touch.
There was no indication of the motive.
Mexico's Interior Ministry says the professors suffered second- and third-degree burns. It says they were able to get themselves to a hospital and are listed in stable condition. Their names haven't been released.