U.S. Army soldiers attached to 2nd platoon, C troop, 1st Squadron (Airborne), 91st U.S Cavalry Regiment, 173rd Airborne Brigade Combat Team protect a wounded comrade from dust and smoke flares after an Improvised Explosive Device blast during a patrol near Baraki Barak base in Logar Province in Afghanistan, Oct. 13, 2012. (Munir Uz Zaman/AFP/Getty Images)

A milestone was reached in Afghanistan Wednesday that has not happened in six years: 30 days without a U.S. military fatality.

It is the longest gap between U.S. military fatalities in Afghanistan since February and March of 2007, when there was a similar 30 day gap.

The winter months in Afghanistan always see a relative reduction in American military casualties as the cold weather and the elements restricts combat engagements.

But this winter season has seen one of the lowest casualty rates in years.

Related: Read More Afghanistan Coverage

In the month of January three U.S. military service members died in the war zone. Two of them died from combat engagements that month and a third died from injuries suffered during an attack in December. In 2012 there were 294 U.S. fatalities in Afghanistan. There are currently 66,000 U.S. troops in Afghanistan. During the previous 30 day gap in early 2007 there were about 25,000 American troops in Afghanistan.

The longest gap in between U.S. military combat deaths took place from December of 2006 thru mid-February of 2007 when there was a 53-day gap.

Military officials will tell you that the number of U.S. fatalities is not a good indicator of security progress in Afghanistan. They point instead to the number of enemy initiated attacks, which have gone down in recent months. They say it also reflects the ongoing transition for security responsibility in Afghanistan to Afghan security forces. NATO and the United States have set the end of 2014 as the deadline for pulling out their combat troops. The Obama administration has yet to decide how many military trainers and counterterrorism troops will remain after that date, though U.S. officials have confirmed that all the options being considered would include fewer than 10,000 troops.

Related: President Obama Announces Quicker Afghanistan Drawdown

Casualty rates among Afghan security numbers are extremely high. According to statistics released by NATO in October, in 2012 Afghan security forces averaged about 535 soldiers and police killed or wounded a month.

In January the British paper The Guardian cited British officials as saying there had been 1,100 fatalities among members of Afghanistan's security forces during the previous six months.