Seven screenshots of Command & Conquer 4 are on the Interwebz today, courtesy of Electronic Arts. For the most part, the shots show off the game's Crawlers.

A Crawler is a massive mobile base that you use to construct units. Having a massive frontline unit that can also build an army is very handy and should lead to some quick offensives but there's a flipside to this: you'll need to protect your Crawler from the enemy or risk crippling your forces. Destroyed Crawlers will eventually respawn but until they do, you'll be unable to build additional units. Also, you'll lose whatever progress you've made with researching upgrades when your Crawler goes down.

Command & Conquer 4 is due in 2010. Only a PC version is planned at the moment.