North Korea has accused the United States of targeting it with anthrax and asked the United Nations Security Council to investigate Washington's "biological warfare schemes" after a live anthrax sample was sent to a US base in South Korea.

"The United States not only possesses deadly weapons of mass destruction ... but also is attempting to use them in actual warfare against (North Korea)," Pyongyang's UN Ambassador Ja Song Nam wrote in a letter to the UN Security Council and UN Secretary-General Ban Ki-moon, which was made public Friday.

North Korea "strongly requests the Security Council take up the issue of the shipment of anthrax germs in order to thoroughly investigate the biological warfare schemes of the United States," Ja said in the letter dated June 4.

He also attached a statement from North Korea's National Defence Commission, which urged the world to consider the anthrax shipment "the gravest challenge to peace and a hideous crime aimed at genocide."

The US mission to the United Nations was not immediately available for comment on the allegations.

Pyongyang's accusation came after the Pentagon recently admitted that live anthrax samples were inadvertently sent to Australia, Canada, Britain, South Korea and laboratories in 19 US states and Washington DC.

US investigators are trying to ascertain whether the shipments of live anthrax stemmed from quality control problems at the US military base in Utah which sent them, Pentagon officials have said.