Updated

U.N. experts plan a low-key re-entry into the weapons inspections business in Iraq, probably heading first for well-known sites inspected in the 1990s to look for signs of new clandestine weapons-making, a U.N. spokesman said Thursday.

After a four-year gap in inspections, the advance U.N. staff was hurrying preparations for next week's first field operations. Specialists had computer disks, satellite photos and intelligence reports to pore through in choosing prime targets for their surprise inspections.

As the U.N. teams readied for months of work — months that could spell the difference between war and peace in Iraq — the NATO alliance warned Iraq anew of "serious consequences" if it fails to cooperate with the effort to deny it chemical, biological and nuclear weapons.

A summit of 19 NATO leaders reaffirmed their governments' support for the U.N. Security Council resolution governing the resumption of inspections. But they didn't threaten any NATO military action if Iraq is defiant, in the way U.S. President George W. Bush has threatened unilateral U.S. military action.

Most governments say they want to see Security Council authorization for any eventual military operations. American allies generally responded noncommitally this week to a U.S. request for support in a potential military move in Iraq.

In Baghdad, the newspaper al-Thawra, organ of President Saddam Hussein's ruling Baath Party, editorialized that Washington cares less about Iraq's weapons arsenals than about a "new-century political strategy" of world domination, "and destroying Iraq is the first step toward achieving this goal."

On leaving Baghdad after two days of talks this week, the chief U.N. inspectors said Iraqi officials told them they would do "everything humanly possible" to cooperate.

The test of that begins next week, when the first operational contingent of 18 inspectors arrives on Monday and the first inspections are expected Wednesday.

"Most likely the inspectors may go back to the sites previously monitored," said Hiro Ueki, spokesman for the inspection agency, the U.N. Monitoring, Verification and Inspection Commission, known as UNMOVIC.

They'll check whether cameras and other surveillance equipment set up at such sites in the 1990s are still functioning, and look for any signs that forbidden weapons activities have resumed during the recent four-year gap in inspections.

The 1991-98 inspection regime dismantled Iraq's nuclear program before it could build a bomb, and destroyed large amounts of chemical and biological weapons and longer-range missiles forbidden to Iraq by Security Council resolutions after the Gulf War. The inspections ended in 1998 amid disputes over access to sensitive Iraqi "presidential sites" and Iraqi complaints that the U.N. operation was infiltrated by U.S. spies.

The resumed inspections are a "final opportunity" for Baghdad to meet its U.N. obligations, the new Security Council resolution says.

Although next week's inspections are unlikely to provoke a showdown with the Iraqis, they're significant for another reason: They'll begin a 60-day countdown to the first comprehensive report by UNMOVIC.

That January report — and any intervening trouble reports from the inspectors — will be closely reviewed by Security Council members as they assess how cooperative Iraq has been.

In planning their inspections, the U.N. experts can draw on mountains of information from many sources. Among them:

—U.S. and other intelligence reports tell of rebuilding at Iraqi sites where inspectors in the 1990s destroyed facilities for making or storing chemical or biological weapons.

—The Iraqi government has turned over computer disks to UNMOVIC that list destinations for recently purchased "dual-use" equipment, technology capable of producing either civilian or militarily useful products.

—The Iraqis must respond to the experts' requests for updated lists of possible witnesses — that is, scientists and technicians who have worked in nuclear, chemical and biological areas of potential military use.

—By Dec. 8, Iraq must make a declaration to the United Nations of all nuclear, chemical, biological and missile-related activities.

That list, collated with outside information, is expected to help the U.N. experts narrow the focus of their inquiry.

Ueki, the U.N. spokesman, said UNMOVIC and the International Atomic Energy Agency, handling the nuclear inspections, have more than 300 specialists available on their rosters. He said typically 80 to 100 inspectors will be in Iraq at one time, a level expected to be reached by year-end.

If the inspectors certify that Iraq has cooperated fully with their disarmament work, U.N. resolutions stipulate that the United Nations should lift international economic sanctions imposed on Iraq after it invaded Kuwait in 1990. The chief inspectors said that could happen as early as one year from now.