Close Quarters Battle (CQB) or close quarters combat (CQC) is a type of fighting in which small units engage the enemy with personal weapons at very short range, potentially to the point of hand-to-hand combat. In the typical CQB scenario, the attackers try a very fast, violent takeover of a vehicle or structure controlled by the defenders, who usually have no easy way to withdraw. Because enemies, hostages/civilians, and fellow operators can be closely intermingled, CQB demands a rapid assault and a precise application of lethal force. The operators need great proficiency with their weapons, but also the ability to make split-second decisions in order to avoid or limit friendly casualties. CQB is defined as a short-duration, high-intensity conflict, characterized by sudden violence at close range.
Criminals sometimes use CQB techniques, such as in an armed robbery or jailbreak, but most of the terminology comes from training used to prepare soldiers, police, and other authorities. Therefore, much CQB material is written from the perspective of the authorities who must break into the stronghold where the opposing force (opfor) have barricaded themselves.
Although there is considerable overlap, CQB is not synonymous with urban warfare, now sometimes known by the military acronyms MOUT (military operations on urban terrain), FIBUA (fighting in built-up areas) or OBUA (Operations in Built Up Areas) in the West. Urban warfare is a much larger field, including logistics and the role of crew-served weapons like heavy machine guns, mortars, and mounted grenade launchers, as well as artillery, armor, and air support. In CQB, the emphasis is on small infantry units using light, compact weapons that one man can carry and use easily in tight spaces, such as submachine guns, shotguns, pistols, and knives.
In a prolonged standoff, the attackers can sometimes bring in specialized equipment for probing the inside of a well-defended area. Sensitive thermal cameras can help locate the occupants, and surveillance personnel can run microphones and fiber-optic cameras through walls, ceilings, and floors. The "throw phones" used to establish contact between authorities and suspects often contain hidden cameras or infrared illuminators for added intelligence-gathering. If hostages escape or can communicate/signal the attackers, they can provide more information from inside.
However, the time and resources to carry out such luxurious preparations are not always there. Not every attacker can field an overwhelming force of specially trained and equipped men with reinforcements standing by. Information about the inside of an enemy-held building or vehicle may not be accessible beyond studying it through binoculars or a rifle scope. While some attackers can go to the lengths of wearing the enemy down by siege or even tunneling under them, others must get the current job done immediately with the force available in order to move on to the next.
The objective is to complete all offensive action before the party being engaged is able to react. To gain this element of surprise, the entry teams use stealth movement and noise/light discipline to get as close to the targets as possible, hopefully putting themselves in a position to engage an enemy from the moment he becomes aware of them. Some teams use subsonic sniper rifles for their initial shots on sentries or dogs.
An assault should come at a time when least expected, taking into consideration fatigue, normal sleep periods, and other factors that detract from the target's alertness. Diversions are an essential element in achieving surprise. Staged emergencies, such as a mock auto accident, fire, or explosion near the crisis site, can divert the target's attention away from the assaulting elements. Explosive breaching and diversionary devices, such as flash bang, smoke, or gas grenades can be employed to distract and disorient the targets. Negotiators can try to manipulate the defenders into a more vulnerable position or convince them that their position will not be stormed.
When law enforcement clears a building, they usually work in a slow and deliberate manner using ballistic shields and mirrors for searching. This affords the highest degree of safety and security for the police, as well as any uninvolved bystanders inside the search area, who can be identified and safely removed without subjecting them to the shock and danger of a sudden assault. When suspects are encountered, the police can confront them with an alert, armed force and try to take control without shooting. If the searchers meet heavy resistance, they can usually pull back without harm and prepare for a dynamic entry.
However, against determined, well-armed opponents who fight in concert to defend an area and keep it under their control, slow stop-and-go movement can cause the deaths of many attackers and hostages. That leads to dynamic entry, used in military operations or hostage rescues. It is the popular image of CQB: a flood of gunmen who burst in without warning and attempt to seize the area. Dynamic entry tactics must be rapid and aggressive, ideally a continuous flow using overwhelming force that does not stop until the threat is eliminated.
In the vast majority of hostage rescue and other dynamic CQB operations, it is desirable to use multiple simultaneous attacks from different entry points to overload the target's ability to react effectively. The more entry points the attackers can choose from, the better their chances. The teams actually entering the objective usually have to synchronize with snipers, negotiators, power technicians, perimeter guards, and others who assist from the outside. Medical personnel, investigators, and bomb experts may be prepped to enter the scene as soon as the initial attackers get control.
It is important that a central commander coordinate all armed elements, not only to better complete a sweep of the target area, but especially to guard against friendly fire. Most assault rifle bullets can go straight through an enemy and still exit with enough force to kill again, so letting enemies get between two attackers (or attacker and hostage) can easily lead to fratricide. Pistol rounds and shotgun pellets carry less risk of overpenetration through a human body, but on a miss, they can still blast through several sheets of drywall and kill unseen people on the other side. When large areas must be searched, leaders will assign boundaries between elements and track them by radio to ensure they do not interfere with each other. The goal is to establish overlapping fields of fire, so that multiple shooters can attack at once from different directions without danger of hitting one another.
Also, it is possible that a point of entry can be created by a precision explosive device to catch the adversary by surprise. An explosive designed for this job is called the Gate Crasher developed by Alford Technologies
The defenders try to stop enemies close to the entry points. The "fatal funnel" is the dangerous area where the assaulter is silhouetted against his own entry point from the perspective of defenders inside the room. Once operators begin to enter, the defenders try to keep them from escaping the fatal funnel. The attackers are also vulnerable from the corners closest to the entry point, the first place from which they can be hit from behind as they enter the room. If the first attackers cannot clear the corners and get out of the fatal funnel, allowing those behind to move in and help, the attack can bog down.
Military uses of close quarters battle vary by unit type, branch and mission. Military operations other than war (MOOTW) may involve peacekeeping or riot control. Specialized forces such as the U.S. Marine Corps specialized units like: RTT, FAST, SRT and U.S. Marine Corps special operations teams such as Recon and MSOB platoons, U.S. Coast Guard or U.S. Navy VBSS (Visit, Board, Search, and Seizure) teams may adapt CQB tactics to their specific needs, e.g. for the boarding compliant and non-compliant vessels at sea. Hostage rescue or extraction by commando troops such as the British or Australian Special Air Service, Delta Force, U.S. Navy SEALs or Sayeret Matkal may involve even more esoteric adaptations or variations, depending on specialized environments, weapons technology, political considerations or a mixture of friendly, unfriendly or civilian personnel.
Armies that often engage in urban warfare operation may train most of their infantry in basic CQB doctrine as it relates to common tasks such as building entry, "clearing a room" and concussion and other grenades.
Police CQB doctrine is also specialized by unit type and mission. Riot control, corrections, the FBI Hostage Rescue Team and SWAT teams, for example, each have different goals, but may make use of similar tactics and technology such as non-lethal force. A prison, for example, may have a squad which specializes in high-risk cell extractions, and psychiatric hospitals or wards often have similar specialized teams. Among the "less-than-lethal" tools and tactics central to police CQB are electroshock guns, pepper spray, riot shields and riot guns to fire tear gas, rubber bullets, plastic bullets or beanbag rounds. However, so-called "less-than-lethal" weapons can still inflict injuries that may result in death.