The United States is waiting for a pattern of Iraqi misbehavior to emerge before going to the U.N. Security Council for debate of military action against Iraq, Defense Secretary Donald H. Rumsfeld said Sunday.

Rumsfeld said Iraqi firings on U.S. and British planes patrolling no-fly zones were "unacceptable" and a violation of the latest Security Council resolution demanding Saddam Hussein disarm. But he said he knew of no immediate U.S. plans to take action because of the shootings.

"It seems to me that what will happen is a pattern of behavior will evolve and then people will make judgments with respect to it," Rumsfeld told reporters flying with him to a defense ministers' summit here.

Since Saddam Hussein grudgingly accepted the latest Security Council resolution Wednesday, Iraq has twice fired on coalition planes enforcing no-fly zones in northern and southern Iraq, U.S. officials say. The latest attack came Sunday, when Iraqi anti-aircraft gunners near Mosul in the northern no-fly zone fired at coalition planes, which responded with airstrikes on Iraqi military positions.

The first team of U.N. weapons inspectors is to arrive in Baghdad Monday to begin preparations for ridding Iraq of its chemical, biological and nuclear weapons programs and the long-range missiles and remote-controlled airplanes to deliver them.

President Bush has threatened to lead "a coalition of the willing" to disarm Saddam through military force if Iraq does not comply with the latest U.N. demands.

Rumsfeld repeated warnings to Iraq's military commanders not to comply if, in the event of an invasion, Saddam orders the use of chemical or biological weapons.

"Let there be no doubt anyone who is involved in the use of weapons of mass destruction will be particularly held accountable in the event it becomes necessary and the president and the U.N. make the decision to use force in Iraq," Rumsfeld said.

He added that the United States understands the bulk of Iraq's regular military forces are conscripts who are "hostages to the small ruling clique." Those soldiers should lay down their arms if war erupts, Rumsfeld said.

"It is certainly correct that people who stay in their barracks and people who do not engage in the use of weapons of mass destruction or attack coalition forces will not have problems," Rumsfeld said.

Rumsfeld said he had not heard of any evidence suggesting that Al Qaeda leader Usama bin Laden had returned to his ancestral homeland of Yemen, where U.S. anti-terrorism operations in recent weeks killed a top leader of the terrorist group. Rumsfeld also declined to comment on a top Al Qaeda leader reported captured recently.

The United States is concerned, Rumsfeld said, about reports of Al Qaeda activity in remote regions of South America and has contacted governments in the area to discuss the problem.

Regional cooperation to fight terrorism, drug trafficking and other threats will be a main theme of Rumsfeld's visit to the Santiago meeting, which brings together defense ministers and other military officials from Western Hemisphere nations.

Rumsfeld plans to speak at the conference's opening session Tuesday before leaving for the NATO summit in Prague later this week.

Rumsfeld said he would propose greater cooperation among countries in the region in maritime operations and in worldwide peacekeeping efforts.

"If one thinks of the problems in the hemisphere of smuggling and narcotrafficking and hostage-taking and the like, the closer we are able to cooperate from the standpoint of our respective navies, the greater the security environment," Rumsfeld said.

The United States is proposing a program to help interested countries in the region improve their naval equipment and information, according to a Pentagon fact sheet. U.S. contributions could include help with communications and logistics, as well as sharing information and helping make sure various countries' systems can work together.