It is primarily used against battlefield fortifications, bunkers, and other protected emplacements. These small fortresses reinforced the line of infantry bunkers. The camps were all crisscrossed with networks of bunkers, trenches, and firing positions. This network of bunkers, tunnels, and pillboxes favored the defense. The Japanese fought most of the battle from underground bunkers and pillboxes. The Japanese bunkers, actually log and earth pillboxes, proved resistant to artillery fire. A developed network of bunkers and fortifications were formed. This network of bunkers and pillboxes favored the defense. The American captives were ordered to build a series of bunkers and fortifications on Wake. Nearly 2,000 al-Qaeda and Taliban fighters fortified themselves in positions within bunkers and caves. Many of the bunkers, batteries and tunnels can still be seen today. Rocket is effective against caves and bunkers. Two other large bunkers stored ammunition. The 9M120F thermobaric variant is used against infantry, buildings, bunkers, and caves. Armament had to be sufficient to suppress or destroy enemy machine gun positions and bunkers.