Why did the UN impose sanctions on Iraq, and how long were they to last?

"The U.N. Security Council imposed comprehensive economic sanctions against Iraq on August 6, 1990, just four days after the Iraqi invasion of Kuwait. When the coalition war had ousted Iraq from Kuwait the following year, the Council did not lift the sanctions, keeping them in place as leverage to press for Iraqi disarmament, return of prisoners of war and other goals. The sanctions have remained in place ever since.

The U.S. and U.K. governments made it clear early on that they would block any lifting of sanctions as long as Iraqi leader Saddam Hussein remains in power. Though the international community increasingly criticized the sanctions because of their harsh impact on innocent Iraqi civilians and their lack of pressure on Hussein, the U.S. and U.K. have blocked many proposed reforms."

"In August 1990, after Iraqi forces invaded Kuwait, the U.N. Security Council passed a resolution under Article VII of the U.N. Charter (thereby making it binding on all U.N. members) that banned all financial transactions with Iraq, international flights to Iraq, and trade with Iraq in all goods except medicine and humanitarian food aid. In April 1991, after the Gulf War ended, the Security Council passed Resolution 687, which determined that the sanctions would continue until Iraq met several conditions, chief among them shutting down its programs to produce chemical, biological, and nuclear weapons and destroying its existing weapons of mass destruction. This resolution also required Iraq to prove to the international community that it was disarmed."