Ulster Defense Association/Ulster Freedom Fighters (UDA/UVF)

The Ulster Defense Association/Ulster Freedom Fighters (UDA/UVF) is the largest loyalist paramilitary group in Northern Ireland, and was formed in 1971 as an umbrella organization for loyalist paramilitary groups. It remained a legal organization until 1992, when the British Government proscribed it.

Ultra, Operation

Operation Ultra was the codename for the British cryptologists efforts at Bletchley Park to intercept and break German coded messages. While Ultra initially was the cryptonym for the project to break the German Enigma machine, the code name came to represent all British efforts to break high-level German radio codes during World War II.

Underground Facilities, Geologic and Structural Considerations in the Construction

Natural and manmade underground facilities have played an important role in warfare and national security for more than 5000 years. Underground chambers were used for hiding places and escape routes in Mesopotamia and Egypt from 3500 to 3000 B.C., and they continue to play an important role in the ongoing conflict in Afghanistan.

Undersea Espionage: Nuclear vs. Fast Attack Subs

In developing its submarines, the United States has tended to pursue technical, rather than numerical, superiority. Such was the case during the Cold War, when the United States led in nuclear submarine development while the Soviets marshaled a much larger submarine fleet.

Unexploded Ordnance and Mines

Munitions (devices equipped with explosives or other material for use in military operations) can represent a hazard to people and to any future use of the land where they are located. As either the accidental or deliberate remnants of military activity, they represent a growing humanitarian and environmental problem in many parts of the world.

United Kingdom, Counter-Terrorism Policy

Prior to the September 11, 2001, terrorist attacks on the United States, counter-terrorism programs in the United Kingdom focused mainly on the Irish Republican Army (IRA), a militant group committed to ending British control of Northern Ireland. After the bombing of Pan Am Flight 103, on its way from London to New York, by Libyan terrorists in December 1988, the British government redoubled its domestic counter-terrorist efforts against a broader range of threats.

United Kingdom, Intelligence and Security

The intelligence community of the United Kingdom is both older and more complicated than that of the United States. MI5, or the Security Service, and MI6, the Secret Intelligence Service, are the best-known components of the British intelligence structure, but these are just two parts of a vast intelligence apparatus.

United Nations Security Council

The United Nations Charter was ratified by its founding members on October 24, 1945. Three years later, the member nations convened the first official meeting of the Security Council, as well as the other UN committees.

United Self-Defense Forces/Group of Colombia (AUC Autodefensas Unidas De Colombia)

The United Self-Defense Forces/Group of Colombia (AUC Autodefensas Unidas de Colombia)—commonly referred to as the paramilitaries—is an umbrella organization formed in April 1997 to consolidate local and regional paramilitary groups each with the mission to protect economic interests and combat insurgents locally. AUC is supported by economic elites, drug traffickers, and local communities lacking effective government security.

United States, Counter-Terrorism Policy

The foundation of the United States counterterrorism policy, according to the U.S.

United States, Intelligence and Security

The United States intelligence and security apparatus is a vast collection of departments, agencies, and offices. It is not a single monolithic entity, although within it is a unified, decentralized group of 14 intelligence and security organizations known as the Intelligence Community (IC).

United States Intelligence, History

From its inception, the United States made use of spies. The nation's first spymaster, General George Washington, recognized the need for accurate intelligence during the Revolutionary War.

Unmanned Aerial Vehicles (UAVs)

Israel was the first nation to make significant use of unmanned reconnaissance drones in combat during operations in Lebanon in 1982. The United States forces began full deployment and use of unmanned aerial vehicles (UAVs) and related technology in the 1990s and UAVs—especially the Predator and Global Hawk—were extensively used by U.S.


Uranium is a radioactive, metallic element with 92 protons and a variable number of neutrons in the nucleus of each atom. There are 16 isotopes of uranium, the most common being uranium-238 (238U).

Uranium Depletion Weapons

Depleted uranium (DU) munitions are armor-piercing or general-purpose ammunition rounds that are composed, in part, of depleted uranium. Depleted uranium is uranium that has had most of its 234U and 235U removed for use in nuclear power or nuclear weapons, leaving metal that is almost entirely 238U.

USAMRICD (United States Army Medical Research Institute of Chemical Defense)

The United States Army Medical Research Institute of Chemical Defense (USAMRICD) located in Aberdeen Proving Ground, Maryland, is a research and training laboratory dedicated to advancing the treatments that alleviate the suffering caused by chemical weapons and developing new materials that aid in those treatments. Researchers at the laboratory include experts in physiology, toxicology, pathology and biochemistry.

USAMRIID (United States Army Medical Research Institute of Infectious Diseases)

USAMRIID is an acronym for the United States Army Medical Research Institute of Infectious Diseases. The facility is operated by the Department of Defense and serves as the country's principal laboratory for research into the medical aspects of biological warfare.

USS Cole

On the morning of October 12, 2000, as the Navy destroyer USS Cole sat anchored in the Yemeni port of Aden, a small boat packed with explosives rammed into its side, tearing a 40-foot hole through the ship's outer hull, killing seventeen sailors and wounding thirty-nine more. It was the deadliest attack against the United States military since 1996, when a truck bomb exploded near an apartment complex in Dhahran, Saudi Arabia, killing 19 American servicemen.

USS Liberty

The Liberty Incident refers to the June 8, 1967, attack on the United States intelligence ship Liberty by Israeli Defense Forces. The Liberty was stationed near the Sinai Peninsula and charged with monitoring Soviet communications to Soviet Arab allies during the Arab-Israeli Six Day War.

USSTRATCOM (United States Strategic Command)

United States Strategic Command, or USSTRATCOM, was formed by a 2002 merger between the Air Force Strategic Command and the U.S. Space Command.


United States President George W. Bush authorized a program on December 13, 2002, which by its conclusion, will see approximately 500,000 military personnel vaccinated against smallpox, along with an equal number of key healthcare providers in the United States.


A vaccine is a medical preparation given to a person to provide immunity from a disease. Vaccines use a variety of different substances ranging from dead microorganisms to genetically engineered antigens to defend the body against potentially harmful antigens.

Variola Virus

Variola virus (or variola major) is the virus that causes smallpox. The virus is one of the members of the poxvirus group (Poxviridae) and it is one of the most complicated animal viruses.

Venezuela, Intelligence and Security

Since civilian government was restored in 1958, the Venezuelan military and intelligence organizations have generally operated under the control of a representative democratic government and a succession of democratically elected presidents.


The Venona Project was the United States Army's Signal Intelligence Service, and later the National Security Agency, operation to intercept and decrypt high-level Soviet diplomatic communications. The project formally began during World War II, though Soviet communications had been monitored occasionally since World War I.

Vietnam War

The Vietnam War was a struggle between communist and pro-western forces that lasted from the end of World War II until 1975. The communist Viet Minh, or League for the Independence of Vietnam, sought to gain control of the entire nation from its stronghold in the north.

Viral Biology

An understanding of the fundamentals of virus structure, genetics, and replication is critical to virologists and other forensic investigators attempting to identify potential biogenic pathogens that may be exploited as agents in biological warfare or by bioterrorists.

Viral Exposure Therapy, Antiviral Drug Development

Several National Institute of Health and Defense Department funded programs are currently attempting to develop drugs that can be used to combat viruses most likely to be used by bioterrorists.

Voice Alteration, Electronic

In most cases, voice alteration technologies are employed to obscure an individual's identity. The ability of to alter the voice, however, also can be very useful in intelligence gathering and espionage.

Voice of America (VOA), United States

The Voice of America (VOA) is a radio, television, and Internet news service that serves as the non-military voice of the United States government by communicating a comprehensive account of America and the world directly to people in other nations. Prohibited by law from broadcasting into the U.S., VOA uses 53 languages while transmitting more than 1,000 hours of news, informational, educational, and cultural programming every week from its Washington, D.C.