(WOMENSENEWS)—Anti-abortion protestors launched a germ-warfare campaign this week against facilities that offer women’s health care.

In an apparently coordinated mailing, 110 Planned Parenthood health facilities and abortion clinics received envelopes containing white powder. At least one tested positive for the bacteria.

Planned Parenthood clinics offer a full range of reproductive health-care services, ranging from dispensing condoms to treating sexually transmitted diseases.

The presence of anthrax in a letter sent to a Planned Parenthood clinic in Stuart, Fla., according to the Florida Times-Union, was confirmed by initial tests. However, the local police department said further tests were being conducted.

The anthrax letter was one of approximately 110 envelopes and packages containing a white power and a letter stating that it was anthrax—sent to abortion clinics and Planned Parenthood facilities nationwide, according to the FBI. Ninety Planned Parenthood centers nationwide reported receiving the letters containing powder, and 20 remaining packages were sent to independent abortion clinics, The Associated Press reported, quoting the FBI.

Initial tests of a few samples did not reveal anthrax. Results of all tests have not been reported.

The FBI said that the mailings appeared to be “a coordinated effort by a radical anti-abortion group to shut down abortion clinics across the nation.”

Vicki Saporta, executive director of the National Abortion Federation, told The AP that threats of biological terrorism are nothing new for abortion providers and clinics.

“We’ve been dealing with domestic terrorism, in terms of biological agents, for more than 10 years,” Saporta said, adding that since 1998 abortion clinics have received more than 80 anthrax threats. None of those anthrax threats was genuine and none of the perpetrators was caught.