"As a result of the injunction, the Department of Defense will pause giving anthrax vaccinations until the legal situation is clarified," the Pentagon said in a statement.

The US District Court for the District of Columbia ordered the injunction on grounds that the US Food and Drug Administration had not done enough to seek public comment before declaring the vaccination safe and effective last December.

The Pentagon has been giving anthrax vaccinations to US troops deployed in high threat areas such as the Middle East and South Korea to protect them against the deadly bacteria.

More than 750,000 troops have been vaccinated against anthrax.