Afghanistan should never be referred to as a small country. It is huge. Even El Salvador, which is slightly larger than Massachusetts, offered guerrilla forces vast territory to hide and long international borders to retreat across. Afghanistan is about the size of Tennessee, Mississippi, Alabama, and Georgia combined.
Maybe by small the writer meant population? Landwise I have the impression of it being vast and mountainous. Sad that a place so beautiful has had to endure all this. :(