Iraq fired yesterday on U.S. and British warplanes patrolling a "no-fly" zone over the southern part of the country, confronting the Bush administration with its first test under the new U.N. resolution insisting Iraq disarm.

The warplanes bombed an Iraqi air defense site about 85 miles southeast of Baghdad in retaliation for the firing, a Pentagon statement said. But the White House gave no indication whether it intended to raise the episode with the U.N. Security Council and use it to justify further military action.

"The administration will have a policy out soon," one senior official said last night. "We've been back and forth" over how to respond. Other officials said no immediate council action was contemplated, but the administration wanted to leave its options open.

Although firing between the patrol planes and Iraqi forces on the ground is relatively frequent, yesterday's was the first reported attack since Iraqi President Saddam Hussein's government accepted the Security Council resolution, which calls for the return of U.N. inspectors to search Iraq for chemical, biological and nuclear weapons. The measure says Iraq cannot "take or threaten hostile acts" against inspectors or U.N. members "seeking to uphold any council resolution," and it warns that any action would constitute a "material breach" of Baghdad's new obligations. Such breaches are to be reported immediately to the Security Council for consideration of further action.

But the "no-fly" zones pose one of the more complicated questions arising from the new measure. Neither it, nor any previous resolution on Iraq, explicitly mentions the patrols. Although the United States and Britain maintain they were implicitly authorized years ago to help protect Iraqi minorities in the northern and southern parts of the country, other U.N. members, including Russia, insist there is no such authorization. While U.N. lawyers over the years have sided against the U.S. interpretation, no formal ruling has ever been made.

President Bush and other U.S. officials have said repeatedly that they believe Iraq's firing on the patrol planes would be a "material breach." But their dilemma in deciding whether to take the matter before the council is that no one else is likely to agree with them.

Chief U.N. weapons inspector Hans Blix, scheduled to arrive in Baghdad Monday, said yesterday his team would be ready to resume inspections Nov. 27. Iraq has said it has no nuclear, chemical or biological weapons programs, and Blix called on the United States or any other country with evidence of secret Iraqi programs to produce it for inspectors.