military groups who have been specially trained to work in a particular area of security, often using methods that are different from the usual ones

They were backed by American special forces on the ground. 他们在地面上得到了美国特种部队的支持。

The military said special forces soldiers had met with a stiff resistance. 军方表示，特种部队的士兵遇到了激烈的抵抗。