Mechanized infantry are infantry troops provided with trucks, armored personnel carriers (APCs), or infantry fighting vehicles (IFVs) for transport and combat. Their support weapons are also provided with motorized transport, or else built directly into combat vehicles, in order to keep pace with the mechanized infantrymen in combat. For units equipped with most types of APC or any type of IFV, fire support weapons such as machineguns, autocannons, or small-bore direct-fire howitzers are often mounted directly on the infantry's own transport vehicles.

History

Mechanized infantry was introduced between World War I and World War II, when French and later German infantry were first provided with trucks or custom built half-tracked and motorized transport for their support units, resulting in highly mobile formations that could keep pace with armored formations when exploiting breakthroughs. As World War II progressed, the Germans integrated tanks or assault guns with mechanized infantry as combined arms Panzergrenadier Divisions, providing mobile anti-tank defense and close-up direct fire support for the infantry.

Most other armies of the period also fielded mechanized infantry in units up to brigade in size. Their armored divisions and some armored brigades also included a mechanized infantry element for combined arms support. Like the Germans, the Soviet army fielded division-sized mechanized infantry units which they called Mechanized Corps, usually consisting of one tank brigade and three mechanized infantry brigades, plus artillery and other support units. New Zealand fielded a division that was sent to Italy, with an organization intermediate between an armored division and a mechanized infantry division.

In the post-war era, the Soviet Red Army and NATO further developed the equipment and doctrine for mechanized infantry. At present, almost all infantry units from industrialized nations are provided with some type of motor transport. Infantry units equipped with IFVs rather than lighter vehicles are commonly designated as "heavy", indicating more combat power but also more costly long-range transportation requirements.

As support for armored formations

It has been discovered repeatedly that armored formations are much less effective without the support of infantrymen; the pre-WWII notion of "tank fleets" has not proved to be sound. Though many nations' armored formations included an organic mechanized infantry component at the start of the war, the proportion of mechanized infantry in such combined arms formations was increased by most armies as the war progressed.

The lesson was re-learned by the Israeli Defense Force in the 1973 war, when a doctrine that relied primarily on tanks, paratroopers, and aircraft proved inadequate. As a makeshift remedy paratroopers were provided with motorized transport and used as mechanized infantry in coordination with the armor; after the war the IDF reorganized its armored formations on the basis of the lesson learned.

The doctrine is now universal in nations capable of supporting armored formations. Recently the US Army has fielded both armored divisions and "heavy" infantry divisions; the organization of the two types was almost identical, except that the ratio of armored battalions to mechanized infantry battalions is slightly higher in the armored divisions and slightly lower in the heavy infantry divisions.

See also

• Armoured combat