North Korea is accusing the United States of targeting it with anthrax and wants the U.N. Security Council to look into it.

A letter from North Korea's U.N. ambassador to the council president and the U.N. chief, made public Friday, claims that the U.S. "possesses deadly weapons of mass destruction" and is trying to use them against his country.

U.S. defense officials disclosed in late May that low concentration samples of live anthrax were shipped to labs in 19 states and four countries. That included a U.S. military facility at Osan Air Base in South Korea.

The anthrax was supposed to have been killed with gamma rays before being shipped.

Officials have said there is no public health risk.