6月28日，一架美军运输直升机在阿富汗东部地区坠毁，机上运有15至20名增援士兵。塔利班已宣布对此事负责。美军发表声明说，飞机坠毁原因、机上人员数量以及是否有人生还，目前尚不得而知。外电报道如下：A U.S. CH-47 Chinook transport helicopter, which a military official said may have been carrying 15 to 20 people, crashed Tuesday while ferrying reinforcements to fight insurgents in a mountainous region in eastern Afghanistan. The Taliban claimed to have shot down the aircraft.

The fate of those on board the helicopter, which crashed near Asadabad in Kunar province, was not immediately known, the U.S. military said. A statement said the cause of the crash was unclear.

Other helicopters and fixed-wing aircraft were sent to the crash site, the military said. Other details were not available, according to U.S. military spokesman Lt. Col. Jerry O'Hara.

Reinforcements在此表示“援军，援舰，增援部队”，例如：Reinforcements were sent to the battlefront.（援兵被派赴前线。）此外，reinforcement表示“增强，加固”，例如：This roof needs some reinforcement.（这屋顶需要加固。）reinforcement therapy（心理学上的强化疗法，凡精神病人做出正常反应即授奖鼓励，以使正常反应逐步强化终至永久固定的疗法。）

据悉，直升机是塔利班用火箭弹击落的。这是今年第二架在阿富汗坠毁的“支努干”直升机。4月6日，一架美军“支努干”直升机在返回巴格拉姆美军基地途中因沙尘暴坠毁，造成15名美军士兵和3名美国平民丧生。