In the first casualties of the year for the United States armed forces, one service member was killed and four others wounded during combat in Achin, Nangarhar province in Afghanistan. According to a statement issued by the U.S. military, the incident took place Monday.

Two of the wounded service members are being treated at a medical facility and are reportedly in stable condition. The other two soldiers injured during the incident have returned to duty, the statement added.

General John Nicholson, commander of U.S. Forces-Afghanistan, said in the statement, "We are deeply saddened by the loss of one of our own. At this very difficult time our heartfelt sympathies go out to the families and friends of our fallen and wounded brothers."

The Islamic State group (also called ISIS) has chosen the Achin district of Nangarhar province in Afghanistan's east to set up its base. Taliban is also known to be quite active in the region. Pentagon did not indicate whether either organization was involved, the New York Times reported.

The Jan. 1 incident that took place in Achin, is a southern district of Nangarhar, along the border with Pakistan. A number of airstrikes and ambushes have occurred in the region last year.

In April, the "mother of all bombs” (MOAB) was launched in the province to combat the suspected Islamic terrorist base there. The attack was a joint operation by the U.S. and the Afghan military forces. No civilian casualties were reported during the strike but 36 militants were killed, according to Afghan officials. However, despite the official claim, ISIS denied suffering any casualties.

There are presently 14,000 US troops in that region of Afghanistan, according to Reuters. Militant groups like Taliban and ISIS have often engaged in combat with each other and launched series of systematic attacks in the area. They are frequently targeted in sustained air strikes and field combat by U.S. troops.