The US Department of Defense said it has directed an immediate safety review at all nine labs and facilities involved in the handling of select agents and toxins.
The review follows the discovery of live anthrax outside a containment area at a military lab in the state of Utah and "incorrect or incomplete record keeping" at two other military labs, Xinhua news agency quoted the department as saying on Thursday.
"The safety review ensures labs will follow appropriate protocols for handling materials, including proper training, record-keeping, and standard operating procedures," a statement said.
The department also said it has expanded the existing suspension of production, handling, testing, and shipment of anthrax to include critical reagents and other agents and toxins.
The suspension applies at all four military labs involved in these activities, including the Utah lab, it said.
"These measures will remain in place pending completion of the ongoing review and investigation until the Army determines it is appropriate to resume operations," the department said.