At least 1,333 British servicemen and women have developed mental health problems after serving in Iraq, the Ministry of Defense (MoD) said on Thursday, as veterans’ groups warned the number could be higher.

A ministry spokeswoman said the figure represented “only 1.5 percent” of the troops who had served in the country and pointed out the cases were not all stress related.

“They could potentially be mental health issues that may have occurred anyway,” she said.

Of the 1,333 cases, 182 had the symptoms of “post-traumatic stress disorder,” 601 of adjustment disorder and 237 of mood disorder. The MoD did not give any details on the remaining soldiers.

“MoD takes the health and welfare of our personnel extremely seriously,” the department said in a statement. “We have a comprehensive policy for the treatment of serving Regulars and Reservists with mental health problems.”

The statement said they had deployed specialist psychiatric personnel to both Iraq and Afghanistan and implemented community-based mental health units across the UK.

But Shaun Rusling, a veteran of the first Gulf war and vice chairman of the National Gulf Veterans and Family Association, was not surprised by the numbers.

“I would imagine they are actually higher, due to soldiers not coming forward due to the fact it would possibly affect their promotion or the ability to stay within the armed forces,” he told Reuters.

“As a Gulf War One veteran, I had hoped that for any future conflict there would be a better set-up but very sadly ... the same thing is happening now that happened 14 years ago,” he said.

Some 6,000 troops reported suffering from an array of illnesses after serving in the first Gulf war. Veterans and their supporters suspected vaccines given to troops or other environmental factors made thousands sick.

The government said no direct link was ever established.

One of the greatest areas of concern following the latest conflict surrounded reservists, Rusling said, who have symptoms missed after returning from the regular army.

The charity Combat Stress, which helps servicemen and women suffering from psychological disabilities as a result of service, said the effects should not be underestimated.

“The effects of these types of illnesses ... can leave service veterans badly damaged and have profound effects on their future lives and those of their families.”