Secretary General Kofi Annan moved quickly to rebut criticism from Congress and elsewhere that he knuckled under to Saddam Hussein by creating a special arrangement for inspecting the eight presidential complexes that the Iraqis hitherto put off limits.

Annan got public support on Thursday from the chief of the U.N. weapons inspection effort, Richard Butler, who said at a news briefing, "This is an agreement that makes me and my organization feel strong, providing Iraq keeps its side of the bargain."Butler, the chairman of the United Nations Special Commission, had been discouraged in recent weeks from making public comments.

The secretary general defended the accord in a letter to U.N. staff members, ostensibly thanking them for supporting his trip to Baghdad last weekend. In the letter, copies of which were given to reporters, Annan told his staff to treat the criticism of his mission with "sympathetic understanding." He appeared to be alluding to critics like the Senate majority leader, Trent Lott, who on Wednesday accused Annan of appeasing Baghdad with concessions.

"It was not unexpected that there would be some criticism of us and misrepresentations of what we have done in Iraq, but you must not be disheartened," Annan said in the letter. "We should all await Security Council action on this agreement," he said. "It is the Council, not a few critics, who will have the last word.

Critics, including some members of the special commission, have expressed concern that the new group created to inspect presidential sites, which will be headed by Jayantha Dhanapala, the U.N. under secretary for disarmament affairs, will weaken the commission's authority.

But Butler insisted: "These arrangements are entirely satisfactory to me and the organization that I lead. They will give us access to the presidential sites in Iraq."

Butler said that he wanted to test the agreement as soon as possible. Asked when the inspectors would try to enter the presidential compounds, he only said, "I hope soon."

Meanwhile, Britain and the United States were pressing other permanent members of the Security Council to back such a resolution that warns Saddam to keep his promise to open sensitive sites to arms inspection or face the "severest consequences."

But China, France and Russia are wary of words that could lead to war. Any of the five permanent members could veto it.

Final consensus on what to do if Iraq violates the accord wasn't expected until next week. On Thursday night, Annan canceled a scheduled trip to Washington on Monday to remain close to U.N. headquarters while the council does its work.