Special forces in the context of "Unconventional warfare"

Combat arms (or fighting arms in non-American parlance) are troops within national armed forces who participate in direct tactical ground combat. In general, they are units that carry or employ weapons, such as infantry, cavalry, and artillery units. The use of multiple combat arms in mutually supporting ways is known as combined arms. In some armies, notably the British Army and Canadian Army, artillery and combat engineer units are categorized as combat support, while in others, such as the U.S. Army, they are considered part of the combat arms. Armored troops constitute a combat arm in name, although many have histories derived from cavalry units.

Artillery is included as a combat arm primarily based on the history of employing cannons in close combat, and later in the anti-tank role until the advent of anti-tank guided missiles. The inclusion of special forces in some armed forces as a separate combat arm is often doctrinal because the troops of special forces units are essentially specialized infantry, often with historical links to ordinary light infantry units.

Marines (or naval infantry) are military personnel generally trained to operate on both land and sea, with a particular focus on amphibious warfare. Historically, the main tasks undertaken by marines have included raiding ashore (often in support of naval objectives) and the boarding of vessels during ship-to-ship combat or capture of prize ships. Marines also assisted in maintaining security, discipline, and order aboard ships (reflecting the historically pressed-nature of the rest of the ship's company and the risk of mutiny). While maintaining many of their historical roles, in modern times, marines also engage in duties including rapid-response operations, humanitarian aid, disaster relief, special operations roles, and counter-terrorism operations. In most nations, marines are an integral part of that state's navy, such as the United Kingdom's Royal Marines or Russia's Naval Infantry; in some countries their marine forces can instead be part of the land army, such as the French Troupes de marine, or, more uncommonly, a nation’s marine forces may be an independent military branch such as the United States Marine Corps or the Ukrainian Marine Corps.

The exact term "marine" is not found in many languages other than English. In French-speaking countries, two terms which could be translated as "marine", but do not translate exactly: troupes de marine (marine troops) and fusiliers-marins (marine riflemen) and fuzileiros navais in Portuguese (lit. 'Naval fusiliers'). The word marine means "navy" in many European languages such as Dutch, French, German, Italian and Norwegian. “Naval infantry” may also refer to sailors forming both temporary and permanent infantry units, such as the British WWI-era 63rd (Royal Naval) Division (an infantry division made-up of Royal Navy sailors and Royal Marines on a semi-permanent basis) or the Imperial Japanese Naval Landing Forces (ad-hoc formations of Imperial Japanese Navy sailors temporarily pressed into service as infantry).

Aircraft hijacking (also known as airplane hijacking, skyjacking, plane hijacking, plane jacking, air robbery, air piracy, or aircraft piracy, with the last term used within the special aircraft jurisdiction of the United States) is the unlawful seizure of an aircraft by an individual or a group. Dating from the earliest of hijackings, most cases involve the pilot being forced to fly according to the hijacker's demands. There have also been incidents where the hijackers have overpowered the flight crew, made unauthorized entry into the cockpit and flown them into buildings—most notably in the September 11 attacks—and in some cases, planes have been hijacked by the official pilot or co-pilot, such as with Ethiopian Airlines Flight 702.

Unlike carjacking or sea piracy, an aircraft hijacking is not usually committed for robbery or theft. Individuals driven by personal gain often divert planes to destinations where they are not planning to go themselves. Some hijackers intend to use passengers or crew as hostages, either for monetary ransom or for some political or administrative concession by authorities. Various motives have driven such occurrences, such as demanding the release of certain high-profile individuals or for the right of political asylum (notably Ethiopian Airlines Flight 961), but sometimes a hijacking may have been affected by a failed private life or financial distress, as in the case of Aarno Lamminparras in Finnair Flight 405. Hijackings involving hostages have produced violent confrontations between hijackers and the authorities, during negotiation and settlement. In several cases – most famously Air France Flight 139, Lufthansa Flight 181, and Air France Flight 8969 – the hijackers were not satisfied and showed no inclination to surrender, resulting in the deployment of counterterrorist police tactical units or special forces to rescue the passengers.

A submarine (often shortened to sub) is a watercraft capable of independent operation underwater. (It differs from a submersible, which has more limited underwater capability.) The term "submarine" is also sometimes used historically or informally to refer to remotely operated vehicles and robots, or to medium-sized or smaller vessels (such as the midget submarine and the wet sub). Submarines are referred to as boats rather than ships regardless of their size.

Although experimental submarines had been built earlier, submarine design took off during the 19th century, and submarines were adopted by several navies. They were first used widely during World War I (1914–1918), and are now used in many navies, large and small. Their military uses include: attacking enemy surface ships (merchant and military) or other submarines; aircraft carrier protection; blockade running; nuclear deterrence; stealth operations in denied areas when gathering intelligence and doing reconnaissance; denying or influencing enemy movements; conventional land attacks (for example, launching a cruise missile); and covert insertion of frogmen or special forces. Their civilian uses include: marine science; salvage; exploration; and facility inspection and maintenance. Submarines can be modified for specialized functions such as search-and-rescue missions and undersea cable repair. They are also used in the tourism industry and in undersea archaeology. Modern deep-diving submarines derive from the bathyscaphe, which evolved from the diving bell.

Special operations or special ops are military activities conducted, according to NATO, by "specially designated, organized, selected, trained, and equipped forces using unconventional techniques and modes of employment." Special operations may include reconnaissance, unconventional warfare, and counterterrorism, and are typically conducted by small groups of highly trained personnel, emphasizing sufficiency, stealth, speed, and tactical coordination, commonly known as special forces (SF) or special operations forces (SOF).

The tagma (Greek: τάγμα; pl.: tagmata, τάγματα) is a military unit of battalion or regiment size, especially the elite regiments formed by Byzantine emperor Constantine V and comprising the central army of the Byzantine Empire in the 8th–11th centuries.

Close air support (CAS) is defined as aerial warfare actions—often air-to-ground actions such as strafes or airstrikes—by military aircraft against hostile targets in close proximity to friendly forces. A form of fire support, CAS requires detailed integration of each air mission with fire and movement of all forces involved. CAS may be conducted using aerial bombs, glide bombs, missiles, rockets, autocannons, machine guns, and even directed-energy weapons such as lasers.

The requirement for detailed integration because of proximity, fires or movement is the determining factor. CAS may need to be conducted during shaping operations with special forces if the mission requires detailed integration with the fire and movement of those forces. A closely related subset of air interdiction, battlefield air interdiction, denotes interdiction against units with near-term effects on friendly units, but which does not require integration with friendly troop movements. CAS requires excellent coordination with ground forces, typically handled by specialists such as artillery observers, joint terminal attack controllers, and forward air controllers.

The Battle of Baghuz Fawqani was an offensive by the Syrian Democratic Forces (SDF), assisted by Combined Joint Task Force – Operation Inherent Resolve (CJTF-OIR) coalition airstrikes, artillery, and special forces personnel, that began on 9 February 2019 as part of the Deir ez-Zor campaign of the Syrian Civil War. The battle—which was composed of a series of ground assaults—took place in and around the Syrian town of Al-Baghuz Fawqani in the Middle Euphrates River Valley near the Iraq–Syria border, and was the territorial last stand of the Islamic State (IS) in eastern Syria.

After corralling IS forces into a densely populated cluster of hamlets and a tent city along the riverside within the first week, the SDF realised that a greater-than-anticipated number of civilians, most of whom were relatives of the what were now mostly foreign IS fighters, were still in the enclave. With CJTF-OIR oversight, the SDF took an incremental approach to the battle, launching assaults then pausing to allow surrendering fighters, hostages, and families to evacuate in order to minimize civilian casualties. The "trickle-out" strategy, coupled with stiff resistance by veteran Islamic State jihadists within a small dense area, prolonged the battle into a protracted siege. The SDF officially declared final victory over the IS in Baghuz Fawqani on 23 March, marking the end of IS-controlled territories in Syria.

The Special Operations Forces of the Armed Forces of Ukraine (Ukrainian: Сили спеціальних операцій Збройних сил України,, romanized: Syly spetsialnykh operatsii Zbroinykh syl Ukrainy, abbreviated ССО, SSO) are the special forces of Ukraine and one of the eight branches of the Armed Forces of Ukraine, with headquarters in Kyiv.

The SSO has the roles including various special forces-related duties such as direct action, special reconnaissance, intelligence gathering, sabotage and psychological warfare. They are not the only special forces units in Ukraine. The SSO was created in 2016, after various reforms of the Ukrainian Armed Forces due to failures in the war in Donbas. The Ukrainian special forces groups were trained on the model of NATO reaction forces. Reorganizing by concentrating the special forces command into a single unified branch. Previously, military Spetsnaz were under the command of the Chief Directorate of Intelligence (HUR), Ukraine's military intelligence service.