Command Sgt. Maj. Kevin J. Griffin

A senior U.S. Army soldier was killed along with a couple of majors by a suicide bomber in Afghanistan, and three special forces soldiers were gunned down by an Afghan commander who had won their trust and invited them to dinner.

The suicide bomber struck Wednesday as a group of U.S. military and civilian officials from the 4th brigade, 4th Infantry Division were in Sarkowi in Kunar Province, which is located in eastern Afghanistan. The suicide attacker detonated an explosive vest near the group, reports ABC News.

Killed in the attack were Command Sgt. Maj. Kevin J. Griffin, 45, of Laramie, Wyo., the brigade's senior enlisted soldier. As a command sergeant major, Griffin was one of the brigade's senior leaders and provided leadership and guidance to the 4,000 man brigade.

Also killed in the blast were Army Maj. Thomas E. Kennedy, 35, of West Point, N.Y., and Air Force Major Walter D. Gray, 38, of Conyers, Ga. Gray was an air liaison officer and flight commander attached to the brigade.

The brigade is tasked with providing security in three provinces that border Pakistan. Based in Fort Carson, Colo., the brigade arrived in Afghanistan this past April.

The explosion also killed American USAID Foreign Service Officer Ragaei Abdelfattah. Another American foreign service officer and an Afghan civilian were also injured in the attack.

In a statement released Thursday, Secretary of State Hillary Clinton praised Abdelfattah's work in eastern Afghanistan over the last year as "critical to our efforts to support Afghanistan's political, economic and security transitions and was an example of the highest standards of service." She said he was so committed to his mission that he had volunteered to serve a second year-long tour in Afghanistan.