Update: NATO’s Resolute Support mission to Afghanistan initially said that a contractor had been killed in the bomb blast. This was incorrect. The contractor is alive and is an Afghan citizen.

Three U.S. service members were killed by an improvised explosive device Monday near Bagram Air Base, Afghanistan.

Three other U.S. service members were wounded in the blast, U.S. Forces-Afghanistan said in a press release Monday afternoon.

A contractor, who is an Afghan citizen, was initially treated along with injured civilians. The contractor was later identified and moved to be treated at Bagram Air Base, Resolute Support officials said in a clarifying statement Tuesday.

The wounded U.S. troops were evacuated and are receiving medical care, officials said.

The Taliban claimed responsibility for the attack through the group’s spokesman, Zabihullah Mujahid. The insurgent group claimed the attack was conducted by a suicide vehicle-borne IED.

“We feel and mourn the loss of these Americans with their families and loved ones. They volunteered to protect their country. We will continue our mission,” said Gen. Scott Miller, commanding general of Resolute Support and USFOR-A.

The identities and units of those killed are being withheld until 24 hours after their next of kin have been notified.

Bagram Air Base is one of the largest U.S. military bases in Afghanistan. The airfield is located in the country’s northern Parwan province.

Despite it’s large size and long-term U.S. presence, Bagram has still been the site of insurgent attacks throughout the years.

In October, an IED detonated near Bagram Air Base, wounding six Czech soldiers as well as multiple civilians.

The U.S. presence in Afghanistan stands at roughly 15,000 troops.

There have been four other U.S. troop deaths in Afghanistan so far this year. Those deaths occurred during combat operations in more remote Afghan provinces.

An Army Ranger died in January of wounds sustained from small-arms fire in Badghis province. Later that same month, an Army Green Beret died after a combat operation in Uruzgan province.

In March, another Green Beret and an explosive ordnance disposal technician were killed during the same mission in Kunduz province.