The Army said Thursday that were 17 reported suicides among active and reserve soldiers in May, more than twice as many as in the previous month.
Of those, one was confirmed and 16 remained under investigation, the Army said.
In April, there were eight reported suicides.
So far this year, there have been 85 reported suicides, 60 percent more than the 51 reported during the same period in 2008.
Combat stress, multiple deployments and associated family issues have been cited as contributing factors to suicides among active and reserve Army soldiers.
Alarmed by the increase in suicides, the Army ordered a suicide-prevention standown for all 1.1 million soldiers, a day off to discuss suicide awareness and prevention, and established a service-wide Suicide Prevention Task Force.
Suicides in the Army increased worldwide from at least 102 in 2006 to 140 last year. Thousands of other veterans are believed to suffer flashbacks, nightmares or fits of anger as they attempt to readjust to civilian life.
To cope with the stress, the Army has set up clinics on most major bases in Iraq, staffing them with psychologists, psychiatrists, social workers and other specialists.
Commanders, chaplains and others in leadership positions are also trained to watch for signs of stress and refer soldiers to mental health professionals if needed.
However, some officials believe soldiers are reluctant to take advantage of the facilities because of the stigma attached to counseling in a military culture that promotes mental and physical toughness.
The Associated Press contributed to this report.