LONDON - The British government said Wednesday that an anthrax vaccine offered to troops who may be deployed to Iraq was safe, although conceded soldiers could suffer side effects.

According to the Gulf War Veterans and Families Association, troops are wary of the inoculation and some have reported feeling sick after receiving an injection.

"Regular servicemen have been phoning us worried about the vaccine, asking for our advice, because they know, like we know, the vaccines are a major cause of our illnesses," said Tony Flint , whose association represents thousands of servicemen who believe they suffer from Gulf War syndrome, the collective name for an assortment of illnesses troops suffered after the U.S.-led 1990-91 war against Iraq.

"From what we have learnt so far, members of the Parachute Regiment have already had the anthrax vaccine and they are reporting to us that they are getting side-effects," he told British Broadcasting Corp. radio.

But the Ministry of Defense insisted the vaccine was safe and said soldiers were being offered it on a voluntary basis.

"I can assure you that it has been given to many, many people over a long period of time and there has never been a case of serious side-effects. Not one case," defense minister Lewis Moodie told the BBC.

"I can assure you the vaccine is safe. It has side-effects, all vaccines like this do. You may get soreness at the site of injection and you may get a flu-like illness after it. But there are no serious complications."

Tens of thousands of Gulf veterans, who received a cocktail of inoculations during the conflict, have complained of illnesses including chronic muscle and joint pain, anxiety, fatigue and memory loss.

In the United States nearly 199,000 U.S. veterans - more than one in four - who served in the Gulf have filed disability claims, according to the Department of Veterans Affairs.

British veterans groups say some 3,000 of the 40,000 Britons who served in the Gulf have reported the illness.

The British government, like the United States, has not formally recognized the existence of Gulf War syndrome and a number of studies have proved inconclusive.