Four men from Georgia in the midst of plotting an attack against American citizens with the use of ricin have been arrested.

The men plotted to purchase explosives and produce a deadly biological toxin to harm both U.S. citizens and government officials, reports the Guardian.

The four men have been identified as Frederick Thomas, 73, from Cleveland; Dan Roberts, 67; Ray H Adams, 65; and Samuel J. Crump, 68, all from Toccoa.

Targets included local police, federal buildings, and federal government employees, such as the Internal Revenue Service.  Other targets were business leaders and members of the media.

These men were part of a fringe domestic militia group, reports the U.S. Justice Department, and have been holding meetings since March 2011 to discuss plans for their terrorist plot.

There is no way for us, as militiamen, to save this country, to save Georgia, without doing something that's highly, highly illegal. Murder, said Thomas during one such meeting, according to court records.

The FBI closely observed these meetings with the help of an informant and an undercover agent, who acted as an explosives and weapons supplier.

Crump was the one who supposedly initiated the use of ricin.

In a September meeting, Crump voiced the idea to make 10 pounds of ricin to spread throughout various U.S. cities.

Ricin is from the castor oil plant and is highly toxic. A dose as minute as a few grains of salt can be lethal to a full-grown adult. Oral exposure to ricin is far less toxic than an injection, thus a greater quantity would need to be distributed to cause damage.

Most victims die between 36 and 72 hours of exposure.

Adams then gave Crump a sample of castor beans to use to produce the ricin, reports the Guardian.

These defendants, who are alleged to be part of a fringe militia group, are charged with planning attacks against their own fellow citizens and government, said Sally Quillian Yates, U.S. District Attorney for the northern Georgia.

While many are focused on the threat posed by international violent extremists, this case demonstrates that we must also remain vigilant in protecting our country from citizens within our own borders who threaten our safety and security, she said.