Nearly 500 active-duty and reserve personnel in the US military killed themselves last year, continuing a trend of unusually high suicide rates that have plagued the US armed force for at least seven years.

The US Defense Department reported Friday that 265 active-duty soldiers in the Army, Navy, Air Force and Marine Corps killed themselves in 2015. Among reserve troops, there were 210 suicides last year.

The number of suicides among troops was 145 in 2001 and began a steady increase until more than doubling to 321 in 2012, the worst year in recent history for soldiers killing themselves.

"Suicide prevention remains a top priority, and the Department will continue its efforts to reduce deaths by suicide among its servicemembers," said Marine Lieutenant Colonel Hermes Gabrielle, a Pentagon spokeswoman.

"Reducing suicide risk entails creating a climate that encourages servicemembers to seek help, reducing access to lethal means and broadening communication and awareness to servicemembers and their families," she added.

The increase in suicide in the military was driven largely by the Army, where 120 suicides were reported last year, the same as in 2013 and down from 124 in 2014.

The suicide rate for the Army in 2012 was nearly 30 suicides per 100,000 soldiers, well above the national rate of 12.5 per 100,000 for 2012.

America's perpetual engagement in overseas wars and the lack of adequate care for veterans returning home are frequently cited as the main reasons behind such alarming suicide figures.

US troops have been at war since 2001 in Afghanistan, and fought in the Iraq war from 2003 to 2011.

By Press TV