WASHINGTON (AP) - The military will resume giving the anthrax vaccine to volunteers as soon as this week, Pentagon officials said Tuesday.

During the next six months, the vaccine will be primarily given to troops who are serving in Korea, the Middle East and South Asia, the Pentagon said in a statement. It will also go to soldiers who work in counterterrorism roles related to defense against biological weapons inside the United States.

They will be informed of the benefits and risks of the vaccine and will be allowed to opt out without penalty, the Pentagon statement said. About one person in 100,000 has a serious adverse reaction to the vaccine, according to the Pentagon.

The military had been prohibited from giving vaccine shots to the troops since October, when a judge found fault in the Food and Drug Administration's process for approving the drug. Previously, hundreds of people were kicked out of the military for refusing the shots out of safety concerns.

In April, U.S. District Court Judge Emmet G. Sullivan said the military could begin giving the vaccine on a voluntary basis under a new law allowing for the emergency use of unapproved drugs.

The Pentagon contends the possibility of anthrax on the battlefield and terrorist attacks constitutes an emergency.

The Defense Department will continue to press for mandatory vaccine shots, said Perry Bishop, a health affairs spokesman for the Pentagon. The military can only administer the vaccine for six months as an emergency measure, officials said.

The Pentagon had given millions of anthrax vaccine shots — in six-shot regimens — to more than 1.1 million troops since 1998. Sullivan's ruling came in a lawsuit filed by six unnamed military personnel and civilian workers who objected to the shots.

Pentagon officials have insisted the shots are safe and effective. But the troubled program has been off-again, on-again for years.

Saying troops should not be used as "guinea pigs," Sullivan ruled in December 2003 that the FDA had never approved the vaccine and issued an order stopping its use on troops. A week later, the FDA approved the vaccine and the shots were resumed, only to be halted again in October over Sullivan's issues with the approval process.

The program also was drawn to a near halt in 2001 and 2002 by shortages of the vaccine. The program started in 1998 with the goal of vaccinating all 2.4 million members of the active and reserve military, but it was radically reduced after factory violations by the nation's sole anthrax vaccine manufacturer left a dwindling supply of the drug.