CNN.com In-Depth Specials

CHINA

China has acknowledged the existence of former chemical weapons production and facilities but not a chemical weapons stockpile. It denies the existence of a biological weapons program although some international intelligence sources said they have evidence to the contrary.

IRAN

Iran is believed to have large stockpiles of chemical and biological weapons.

IRAQ

Iraq has acknowledged claims that it possessed missiles tipped with biological weapons during the 1991 Persian Gulf War. After the war, the U.N. Security Council established a special commission, UNSCOM, to oversee the destruction of Iraq's stockpiles of chemical and biological weapons, which some experts believe include mustard gas and sarin among other lethal agents. UNSCOM is no longer operating in Iraq, and the current size and scope of the country's chemical and biological weapons program is unknown.

ISRAEL

Israel does not disclose details about its alleged chemical and biological weapons program.

LIBYA

Libya is believed to possess a chemical weapons stockpile and is researching biological weapons capability. The scope of its program is unknown.

NORTH KOREA

North Korea is suspected of possessing a large stockpile of biological and chemical weapons. The program is run by the country's Nuclear-Chemical Defense Bureau, established in 1981.

RUSSIA

During the past decade, Russia has committed to dismantling its chemical and biological weapons program and destroying its stockpiles of such weapons, believed to be the largest in the world. The breakup of the Soviet Union and Russia's economic crisis have raised fears that scientists who formerly worked in the Soviet chemical and biological weapons program would sell supplies or expertise to other countries.

SOUTH KOREA

South Korea has declared the existence of a chemical weapons stockpile and has committed to dismantling its production facilities. It is not known to have biological weapons capability.

SYRIA

Syria is believed to have a stockpile of chemical weapons and is thought to be pursuing biological weapons capability. The scope of its program is not known.

TAIWAN

Taiwan is suspected of pursuing chemical weapons capability. It is also suspected of proliferating biological weapons technology, but there is no conclusive evidence.

UNITED STATES

The United States said it does not maintain a stockpile of biological weapons although it does pursue defensive biological research. It has what it is believed to be the world's second largest stockpile of chemical weapons, which it has committed to destroying by 2004.

The following is a list of some of the countries commonly cited by experts as having probable or known involvement in chemical and/or biological weapons. However, many other countries are suspected of having such programs.

Click on the countries for more information.

Click to learn more about biological weapons

Biological Weapons

Click to learn more about chemical weapons

Chemical Weapons

Source: Center for Defense Information, an independent military research organization in the United States, the Center for Nonproliferation Studies at the Monterey Institute of International Studies, and CDC.