Kristin Murphy, Deseret News via AP
This Feb. 19, 2015 photo shows Referee Module No. 2 of the Whole System Live Agent Test at Dugway Proving Ground in Dugway, Utah. Centers for Disease Control and Prevention is investigating that aspect of what went wrong at Dugway Proving Ground, the Army installation in Utah that sent the anthrax to government and commercial labs in nine states across the U.S. and to an Army lab in South Korea.

WASHINGTON — What military officials described last week as a few errant shipments of potentially live anthrax with minimal public risk has become a larger problem, with officials acknowledging Tuesday that they don’t know for sure how many research samples of the deadly pathogen were mistakenly sent to labs across the world.

Originally, the Pentagon said the shipments from the Army’s Dugway Proving Ground in Utah had gone to labs in nine states and a U.S. military base in South Korea.

Since then, three more states and two countries have been added to the list, and military officials admitted Tuesday that it could grow longer. A sample even was sent to an outbuilding on the Pentagon’s Virginia campus.

So far, no one is known to have been sickened, but the widening problem indicates a serious breach in how the government handles dangerous biological materials.

“The department is in the process of determining the scale and scope of this,” Army Col. Steve Warren, a Pentagon spokesman, told reporters. “The department’s shipment and transport of anthrax spores has stopped.”

The Pentagon on Tuesday added Washington and Canada to the states and countries where labs received potentially live anthrax samples from the Army testing facility in Utah.

The new disclosure brought to 12 the number of states where labs received the suspect anthrax. The Pentagon previously had said suspect anthrax also had been sent to Australia.

“We yesterday determined that we had shipped anthrax to Canada,” Warren said. “The anthrax that we shipped — the master sample that it came from at Dugway — tested to be live.”

The Canadians had been notified and were testing the anthrax spores received there.

Warren also disclosed for the first time that three different large samples at the Dugway Proving Ground had been found to contain live anthrax, increasing the likelihood that additional labs in more states and countries might have received some.

The anthrax was supposed to have been killed with radiation before leaving the Dugway facility as part of a program to develop a field test to identify biological threats in the environment.

Asked whether the Pentagon had ruled out malfeasance by personnel at the Dugway Proving Ground, Warren responded: “We have to let the investigation play out.”

In a later email, Warren said that some of the live anthrax had been sent to what he described as an outbuilding on the Pentagon premises, partial confirmation of a CNN report that the Pentagon Force Protection Agency, the massive complex’s separate police force, had possibly received some of the deadly pathogen.

Even before the new disclosures, the inadvertent shipment of live anthrax had angered Congress, with senior lawmakers firing off letters to Defense Secretary Ash Carter, Army Secretary John McHugh and Tom Frieden, director of the Centers for Disease Control and Prevention (CDC).

Warren continued to downplay the threat. “There is no risk to the public at this point,” he said.

Last week, the Pentagon said that 22 personnel at the Osan Air Base in South Korea had started taking the antibiotic Cipro as a precautionary measure.

The CDC was leading a global investigation into the growing problem, while the Pentagon started an internal probe aimed at determining how at least three anthrax samples at Dugway had some live anthrax spores when the spores were believed to have been killed through radiation.

Before the disclosures Tuesday, the Pentagon had said that 24 commercial, university or military research labs in 11 states plus South Korea and Australia had received the errant shipments.

The 11 states were California, Texas, Utah, Wisconsin, Tennessee, Massachusetts, New York, New Jersey, Delaware, Maryland and Virginia.

Warren declined to say how many additional labs, in Washington state and Canada, had received suspect anthrax.

“I know there is a rush to get every little micron of information out there,” Warren said. “We want to be as transparent as possible, but we also want to be as precise as possible.”

Indicating the seriousness of the problem, the Pentagon was trying to arrange a briefing for reporters to be held Wednesday with a top military scientist, a physician and other senior experts on anthrax.

A lab in Maryland, which first notified CDC of the problem, is the only known research center to have cultured live anthrax from the sample it received from Dugway.

The Pentagon investigation was looking at how the large anthrax samples are radiated, how they are then tested to ensure that all spores have been deactivated, and how they are delivered to research labs throughout the United States and beyond.