A radical group that opposes nanotechnology has has claimed responsibility for at least two bombing attacks on researchers in Mexico and it praises the “Unabomber,” whose mail-bombs killed three people and injured 23 in the United States.

A manifesto posted Tuesday on a radical website mentions at least five other Mexican researchers whose work it opposes, and lauded Theodore Kaczynski, who is serving a life sentence for bombs that targeted university professors and airline executives.

It was issued in the name of a group whose title could be translated as “Individuals Tending Toward the Savage.”

Mexico State prosecutors’ spokesman Sonia Davila said authorities are investigating the authenticity of the manifesto, but said its description of how the dynamite-stuffed pipe-bomb was constructed matched evidence found at the scene of a small explosion Monday at Monterrey Technological Institute’s campus in the State of Mexico, on the outskirts of the capital. Officials had not revealed details of the device that injured two professors.

The attacks caused some universities to take extra security precautions Wednesday. Officials at the campus hit by Monday’s bombing said that metal detectors would be used at access points, vehicles entering the campus would be inspected, dogs would be used to detect suspicious artifacts, visitors would have to have an escort while on campus and student or faculty IDs would be required to enter the campus.

A police bomb squad removed a suspicious package left Tuesday at a Mexico City research institute, but an institute spokeswoman later told local media the package simply contained books.

Nanomaterials are made of extremely tiny particles, some thousands of times finer than a human hair, which have come increasingly into use in recent years, often in products such as skin care and cosmetics. Consumer advocates and others have raised questions about potential risks from these materials.

The manifesto expressed fears that that nanoparticles could reproduce uncontrollably and form a “gray goo” that would snuff out life on Earth.