sentences:  In 2007, Bagram was the main US airbase in Afghanistan.On February 27, at about 10 am local time, a suicide bomber attacked the outer gate of the base, killing 23 people and injuring at least 20 others.Among the dead were U.S. soldier PFC Daniel Zizumbo; a U.S. contractor; SSG Yoon Jang-ho, a South Korean soldier; and 20 Afghan workers at the base.