“When these modified viruses affect the way we live through a nano-bacteriological war, unleashed by some laboratory error or by the explosion of nano-pollution that affects the air, food, water, transport, in short the entire world, then all of those who defend nanotechnology and don’t think it is a threat will realize that it was a grave error to let it grow out of control,” according to statement by the group.

The manifesto said the bomb was directed at professor Armando Herrera Corral, who is listed on the university’s website as a specialist in information technology. But the group also expressed satisfaction that professor Alejandro Aceves Lopez, an expert in robotics technology, also was injured in the blast.

Prosecutors say Herrera Corral brought the package to his colleague’s cubicle to show it to him, when it exploded.

The statement also claimed responsibility for attacks at another university in April and May against professor Oscar Camacho, listed by Mexico’s National Polytechnical Institute as a specialist in micro-electro-mechanical systems. His academic background includes computer and electronic engineering.

The ITS statement said Camacho’s “police impulses” to inspect the package triggered the detonator, adding that “there is no doubt that curiosity killed the human.”

The group praises the “Unabomber,” whose mail-bombs killed three people and injured 23 in the United States.

Jorge Lofredo, an Argentine expert on regional armed movements, said that the group appears to be relatively new. He said that most anarchist groups avoid violent acts, and noted that previous Mexico City blasts blamed on anarchists were small and sought to avoid causing injuries.

The group’s statement suggested the bombing would not be the last.