Here's a look at weapons inspections in Iraq from 1991 to 2007.
At the end of the 1990-1991 Persian Gulf War, the United Nations passed Security Council Resolution 687 setting the terms for the cease-fire between Iraq and the US-led coalition. Section C of the resolution called for the elimination of Iraq's weapons of mass destruction and some ballistic missiles and established the United Nations Special Commission (UNSCOM).
Timeline: April 3, 1991 - The United Nations passes Security Council Resolution 687.
April 6, 1991 - Iraq accepts SCR 687.
April 18, 1991 - Under the terms of SCR 687, Iraq gives a detailed account of its weapons inventory and denies it has a biological weapons program.
June 9, 1991 - UNSCOM begins its first inspection looking for chemical weapons.
June 23-28, 1991 - Iraqis fire warning shots at inspectors to prevent them from intercepting vehicles suspected of carrying nuclear equipment.
June 30, 1991 - UNSCOM begins its first missile inspection.
August 2, 1991 - Iraq admits to biological weapons research for "defensive purposes" only.
August 15, 1991 - The UN Security Council passes SCR 707, demanding that Iraq reveal all of its prohibited weapons and weapons programs.
September 6, 1991 - Iraq blocks the use of helicopters by UNSCOM teams.
September 21-30, 1991 - IAEA inspectors discover documents relating to Iraq's nuclear weapons program. Iraqi officials prevent the inspectors from leaving the site for four days.
October 11, 1991 - The United Nations passes SCR 715. It outlines the plans for ongoing monitoring and verification in Iraq. In response, Iraq says that SCR 715 is unlawful and that it's not ready to comply.
March 19, 1992 - Iraq declares that it once possessed 89 missiles and chemical weapons, but destroyed them in the summer of 1991. This unilateral destruction of weapons is a violation of SCR 687.
June 1992 - Iraq delivers its first "Full, Final and Complete Disclosure" on its chemical weapons programs.
July 1992 - UNSCOM destroys some Iraqi chemical weapons and production facilities.
July 6-29, 1992 - Inspectors are prevented from searching the Ministry of Agriculture by Iraqi officials. They stage a 17 day sit-in.
July 5, 1993 - UNSCOM leaves Iraq.
November 26, 1993 - Iraq accepts the terms of SCR 715.
June 1994 - UNSCOM destroys material and equipment relating to chemical weapons production.
October 15, 1994 - SCR 949 passes. The resolution demands that Iraq begin cooperating with UNSCOM and withdraw its troops massed on the border with Kuwait.
March 1995 - Iraq releases its second "Full, Final and Complete Disclosure" of biological and chemical weapons programs.
July 1, 1995 - Iraq admits the existence of its biological weapons program.
August 1995 - Iraq releases the third "Full, Final and Complete Disclosure" relating to its biological weapons programs.
November 1995 - Iraq delivers its second disclosure report on its missile programs.
December 16, 1995 - UNSCOM has the Tigris River near Baghdad searched. They uncover over 200 missile parts, believed to have originated in Russia.
May 1996 - Al-Hakam, a facility used to produce biological weapons agents, is destroyed.
June 1996 - Iraq releases a revised third "Full, Final and Complete Disclosure" on its biological weapons programs.
September 25, 1997 - During an inspection of a food laboratory, inspectors seize suspicious documents concerning bacteria and chemicals. The documents originate from the Iraqi Special Security Office. UNSCOM is prevented from inspecting SSO's headquarters.
August 5, 1998 - Iraq decides to suspend cooperation with UNSCOM until its demands for an end to the embargo and a reorganization of UNSCOM are met.
September 9, 1998 - The UN Security Council passes SCR 1194, condemning Iraq's lack of cooperation.
October 31, 1998 - Iraq stops all UNSCOM inspections.
November 18, 1998 - Inspectors return to Iraq.
December 1, 1998 - Iraq halts cooperation with inspectors.
December 15, 1998 - Chief weapons inspector Richard Butler delivers a report to the UN Security Council which details Iraq's lack of cooperation on inspections.
December 16, 1998 - Weapons inspectors leave Iraq.
December 17, 1998 - US and British forces launch air strikes against Iraq. Operation Desert Fox lasts for four days.
January 8, 1999 - The United States admits that UN weapons inspectors installed surveillance equipment used to spy on Iraqi leader Saddam Hussein.
December 17, 1999 - Security Council Resolution 1284 replaces UNSCOM with the United Nations Monitoring, Verification and Inspection Commission (UNMOVIC).
January 29, 2002 - US President George W. Bush labels Iraq part of an "axis of evil" in his State of the Union speech.
September 16, 2002 - Iraq agrees unconditionally to the return of inspectors.
September 19, 2002 - Iraqi Foreign Minister Naji Sabri delivers a letter to the UN from Hussein stating that Iraq has no chemical, nuclear or biological weapons.
October 1, 2002 - The UN and Iraq agree on terms they say are consistent with existing UN resolutions. The United States threatens to veto unless a US resolution is approved that would allow military action for non-compliance by Iraq.
November 8, 2002 - The UN Security Council passes Resolution 1441.
November 13, 2002 - Iraq delivers a letter to UN Secretary General Kofi Annan, accepting the terms set forth in resolution 1441.
November 27, 2002 - Inspections resume in Iraq.
December 7, 2002 - Iraq submits a 12,000-page report on its WMD programs.
January 16, 2003 - Inspectors discover 12 chemical warheads, 11 of them empty, at the Ukhaider ammunition storage area.
January 20, 2003 - After two days of negotiation, Hans Blix, Mohamed ElBaradei, and Iraqi officials reach an agreement about Iraqi cooperation and concessions regarding the inspections.
February 5, 2003 - Secretary of State Colin Powell briefs the UN Security Council on inspections. He presents evidence that the United States says proves Iraq has misled inspectors and hid proscribed weapons and equipment.
February 14, 2003 - Blix and ElBaradei brief the UN Security Council. Blix reports that the inspectors have not yet found any weapons of mass destruction in Iraq. Blix also reports that Iraq is in violation of UN resolutions concerning its al Samoud 2 missile program.
February 19, 2003 - Inspectors visit a factory northwest of Baghdad and tag 32 al Samoud 2 missiles.
February 27, 2003 - Iraq agrees to destroy the country's al Samoud 2 missile stock. However, the letter doesn't specify a date that the missile destruction will begin.
March 18, 2003 - Inspectors withdraw from Iraq.
March 19, 2003 - Bush announces US and coalition forces have begun military action against Iraq.
October 2, 2003 - David Kay, who heads the US search for weapons of mass destruction, reports to congressional intelligence committees that the Iraq Survey Group has found no such weapons in Iraq. Kay says he will need six to nine months to conclude his work.
January 28, 2004 - After retiring earlier in the month, Kay tells the Senate Armed Services Committee that there should be an independent investigation into the flawed intelligence about Hussein's weapons capability.
February 6, 2004 - Bush names a seven-member commission to investigate the nation's intelligence operations, specifically to study the information about Iraq possessing weapons of mass destruction.
October 6, 2004 - The final Iraq Survey Group report is released. The report concludes that Hussein did not possess weapons of mass destruction.
March 2005 - The Special Advisor to the Director of the CIA issues addendums to the Iraq Survey Group Comprehensive Report after additional investigations.
March 31, 2005 - The Commission on the Intelligence Capabilities of the United States Regarding Weapons of Mass Destruction reports that the intelligence community was "dead wrong" in its assessments of Iraq's weapons of mass destruction capabilities before the US invasion.
December 2005 - US inspectors end their search for weapons of mass destruction.
June 29, 2007 - The UN Security Council adopts resolution 1762, terminating the United Nations Monitoring Verification and Inspection Commission's (UNMOVIC) mandate.