The number of suicides was higher than the death toll from combat in 2012 in Afghanistan, where 310 American troops were killed, according to an independent tally by icasualties.org.
The 349 suicides among active-duty service members was up from 301 the previous year, officials said Monday.
US military leaders and civilian officials have struggled to contain the problem and launched an array of programs to try to address it.
But it remains unclear why the suicide rate continues to climb, as a significant number of troops who take their lives have not faced combat.
Officials say the military still has a lower rate of suicides than the civilian population.
The civilian suicide rate for men aged 17-60 was 25 per 100,000 in 2010, while the military`s rate last year was 17.5 suicides per 100,000.
The rising number of suicides, which officials and lawmakers refer to as an epidemic, has been blamed on the strain of more than a decade of war, which has fueled mental health problems, alcohol and drug abuse and high divorce rates.
The US Army had 182 suicides last year, the highest number among the armed services.
The Marine Corps saw a 50 percent spike in suicides, with 48 Marines taking their lives.
The Air Force reported 59 suicides, a 16 percent increase, and the Navy had 60, a 15 percent rise compared to the previous year.(*)
Editor: Heru Purwanto
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