CNN has reported that more US soldiers killed themselves last month than in recent Army history.

Statistics from the US Army have revealed the grim trend, which saw 32 soldiers commiting suicide in June, the highest number in a single month since the Vietnam era.

Twenty-one of them were on active duty, while 11 were in the National Guard or Army Reserve.

Seven soldiers killed themselves while serving in Iraq and Afghanistan.

Army officials have had to admit they are still unsure why troops are committing suicide at a record rate as trends have not been established from any one unit or station.

Including the June numbers, 145 soldiers have killed themselves this year, more than half of the total number for all of 2009.