WASHINGTON (AFP) - The Pentagon said on Tuesday that it sent live anthrax to a lab in Britain, one of a growing number of places where the US military mistakenly shipped the potentially lethal bacteria.

The lab in Britain along with another facility in Massachusetts brought the total number of laboratories that have received live anthrax samples to 68, and an investigation into the case is still underway, Pentagon spokesman Colonel Steven Warren said.

"The grand total is now 68 labs," Warren said. Four countries outside the United States have received samples: Australia, Britain, Canada and South Korea. Nineteen US states also have been affected, as well as the US capital Washington.

Senior defense officials admitted last week the problem of mistaken shipments was worse than initially reported and that the extent of the problem remained unclear. But officials have insisted there is no threat to public health and that the small concentrations of live anthrax had been shipped in several layers of air-tight packaging.

At least four batches of live anthrax have been found among a total of 400 batches or "lots" held at military facilities. So far all the active bacteria has turned up at Dugway Proving Ground, a US Army lab in Utah.