Authorities in Pakistan said that a package containing white anthrax powder was sent to the office of Prime Minister Yusuf Raza Gilani.
A spokesman for Gilani, Akram Shaheedi, says the package was received in October and was thought to have been sent by a woman who is a professor at Jamsboro University in the southern province of Sindh.
No one became ill from the package and the motive of the woman who allegedly mailed it was not immediately clear.
The spokesman also did not say why the news was being made public now or whether the woman had been arrested.
Compiled from agency reports