of calibers. Different bands were used for different types of weapons—field guns, mortars, anti-aircraft guns and coastal guns. Modern operations List of countries in order of amount of artillery (only conventional barrel ordnance is given, in use with land forces): Artillery is used in a variety of roles depending on its type and caliber. The general role of artillery is to provide fire support—"the application of fire, coordinated with the manoeuvre of forces to destroy, neutralize or suppress the enemy". This NATO definition makes artillery a supporting arm although not all NATO armies agree with this logic. The italicised terms are NATO's. Unlike rockets, guns (or howitzers as some armies still call them) and mortars are suitable for delivering close supporting fire. However, they are all suitable for providing deep supporting fire although the limited range of many mortars tends to exclude them from the role. Their control arrangements and limited range also mean that mortars are most suited to direct supporting fire. Guns are used either for this or general supporting fire while rockets are mostly used for the latter. However, lighter rockets may be used for direct fire support. These rules of thumb apply to NATO armies. Modern mortars, because of their lighter weight and simpler, more transportable design, are usually an integral part of infantry and, in some armies, armor units. This means they generally do not have to concentrate their fire so their shorter range is not a disadvantage. Some armies also consider infantry operated mortars to be more responsive than artillery, but this is a function of the control arrangements and not the case in all armies. However, mortars have always been used by artillery units and remain with them in many armies, including a few in NATO. In NATO armies artillery is usually assigned a tactical mission that establishes its relationship and responsibilities to the formation or units it is assigned to. It seems that not all NATO nations use the terms and outside NATO others are probably used. The standard terms are: direct support, general support, general support reinforcing and reinforcing. These tactical missions are in the context of the command authority: operational command, operational control, tactical command or tactical control. In NATO direct support generally means that the directly supporting artillery unit provides observers and liaison to the manoeuvre troops being supported, typically an artillery battalion or equivalent is assigned to a