The international effort to locate and eliminate Iraq's most dangerous weapons is coming to a head. U.N. inspectors issued an update yesterday on their recent search efforts.

Q: What is the dispute about?

A: The Bush administration and many of its foreign allies believe Iraqi President Saddam Hussein is hiding evidence of illegal projects to produce biological, chemical and nuclear weapons. Hussein and his aides insist they are doing no such thing.

Q: What does the United Nations say about this?

A: After the 1991 Persian Gulf War, the U.N. Security Council ordered Iraq to disclose all it had done to build weapons of mass destruction and missiles able to travel more than about 93 miles. Hussein and the United Nations dueled for years, finally driving inspectors to abandon their search in 1998. But in November, prodded by the United States and Britain, the 15 council members voted unanimously that Iraq had violated U.N. commands.

Q: Then what happened?

The Security Council gave Iraq 30 days to reveal everything about its weapons programs, including the location of any poison gas, nerve agents, missiles and anything needed to make them. The council told Iraq to give U.N. inspectors immediate access to any buildings, equipment and documents they wanted to examine, as well as lists of anyone ever associated with the projects.

Q: What are inspectors trying to find?

A: The search is mainly focused on weapons acquired by Iraq before the Gulf War. Iraq said it destroyed much of its biological and chemical stockpile, but inspectors have discovered significant discrepancies. Iraqi documents acquired by inspectors in the 1990s suggest, for example, that Iraq produced far greater amounts of anthrax and the deadly nerve agent VX than it admitted. Inspection teams also are looking for evidence of new attempts to acquire banned weapons.

Q: How do the inspectors know where to look?

A: Inspectors started by searching facilities associated with Iraq's past weapons programs. Satellite photographs had shown construction activity in some cases, suggesting that Iraq might be rebuilding its old weapons factories. More recently, the inspectors began visiting private homes, farms and businesses, apparently acting in response to information supplied by Western intelligence agencies or Iraqi defectors.

Q: Are things going smoothly?

A: The chief U.N. inspectors -- Hans Blix and Mohamed ElBaradei -- delivered preliminary findings yesterday. Blix said Iraq has been cooperating on the "process" of inspections -- allowing inspectors prompt access to sensitive sites, for example -- but not on the "substance." He criticized Iraq for not encouraging its weapons scientists to submit to U.N. questioning and for failing to answer scores of questions about previous arsenals and long-range missile programs. ElBaradei said his teams had found no evidence that Iraq had attempted to rebuild its former nuclear weapons program.

Q: France, Russia and other key Security Council countries say the inspectors should be given more time. Why?

A: Blix and ElBaradei want to know more about the history of Iraq's weapons projects. They say they need more time to interview Iraqi scientists and workers. In a meeting with U.N. officials last week, Iraq promised to provide more information and delivered the names of dozens of scientists omitted from previous lists.

Q: But Secretary of State Colin L. Powell keeps saying time is running out. What's the hurry?

A: Powell believes Hussein has no intention of complying with the Security Council's demand. He said last weekend that the longer Hussein is allowed to evade the United Nations, the greater the chance he will use illegal weapons or give them to terrorists. Also, if confrontation turns to war, military commanders worry about the Iraqi desert heat, which becomes more punishing as winter turns to spring.

Q: What happens now?

A: Members of the divided Security Council will begin meeting this week to decide whether an invasion of Iraq will soon be necessary. President Bush has said the United States is willing to invade Iraq without U.N. approval if Hussein's stance does not change. A decision is expected within weeks.