WARCABULARY: It's apparent we may need to brush up on our war vocabulary. Or at least I need to. A refresher:

siege
The sitting of an army around or before a fortified place for the purpose of compelling the garrison to surrender; the surrounding or investing of a place by an army, and approaching it by passages and advanced works, which cover the besiegers from the enemy's fire.

Source: The American Heritage® Dictionary of the English Language, Fourth Edition
Copyright © 2000 by Houghton Mifflin Company.

invasion, incursion, irruption, inroad
Invasion is the generic term, denoting a forcible entrance into a foreign country. Incursion signifies a hasty and sudden invasion. Irruption denotes particularly violent invasion. Inroad is entry by some unusual way involving trespass and injury.

Source: Webster's Revised Unabridged Dictionary, © 1996, 1998 MICRA, Inc.