LEXINGTON, Ky. (AP) _ At least 14 letters claiming to include  anthrax and mailed to abortion and Planned Parenthood centers  across the nation this week were postmarked in Lexington, a postal  inspector said.  

Initial tests show that the threats received Thursday and Friday  were hoaxes, similar to the anthrax warnings sent to clinics in  Louisville and other U.S. cities in October.  

Doug Ostwalt, who heads the Louisville postal inspection office  and is a member of a federal task force investigating the letters,  said authorities believe all the threats are connected.  

The Lexington-postmarked letters containing explicit threats  were reported at abortion clinics or Planned Parenthood centers  Thursday in Milwaukee; Cincinnati; Washington, D.C.; Manchester,  N.H.; Rapid City, S.D.; Asheville, N.C.; Charleston, S.C.; and  Sioux Falls, S.D., Ostwalt said.  

Other letters was received Friday in Birmingham, Ala., Des  Moines, Iowa; and several cities in Vermont, Ostwalt said in  today's Lexington Herald-Leader.  

Anthrax mostly affects farm animals, but its germs, when inhaled  by humans, can cause flu-like symptoms and can lead to death if not  treated early enough with antibiotics.  

Phony anthrax threats have been very common in recent months,  including the October incidents affecting abortion clinics in four  states. It is a federal felony to send an anthrax threat, even if  it is a hoax.  

U.S. Attorney General Janet Reno has created a national task  force to prosecute and prevent threats against other abortion  providers.