WASHINGTON (AP) - Small groups of American diplomats, intelligence analysts and officials periodically infiltrate northern Iraq to confer with Kurds and other opponents of the Baghdad government.

They apparently operate freely. The area is protected by U.S. and British military overflights and is beyond the reach of Iraqi President Saddam Hussein's air force.

The Americans' purpose is an unabashed, mostly psychological campaign to rattle the Iraqi leader, who so far has withstood years of U.S. demonizing and U.N. sanctions engineered by Washington.

Taking military action is, so far, only a theory.

The main Iraqi opposition group, the Iraqi National Congress, has produced no plan of action that holds promise of success, a senior U.S. official said Tuesday. As a result, the United States has approved no military move inside the country and is not attempting one of its own.

President Bush is considering military as well as diplomatic and political tactics, however, to try to end the rule of a leader he denounced last month as part of an ``axis of evil'' with leaders of Iran and North Korea.

U.S. air patrols of Iraq's no-fly zones have remained constant since Sept. 11, when terrorists destroyed the World Trade Center and heavily damaged the Pentagon and touched off a worldwide U.S. campaign against terror groups and countries that support them.

Saddam's refusal to admit U.N. weapons inspectors for more than three years has heightened worry that his programs to develop weapons of mass destruction are advancing. Combined with Iraq's support for terror - it is one of seven countries so branded by the State Department - the threat posed by Iraq's behavior is considered unequaled by administration analysts.

Still, U.S. warplanes have launched fewer retaliatory strikes against Iraqi targets since Sept. 11, because the Iraqis are firing at the U.S. planes less frequently, said Lt. Col. Dave Lapan, a Pentagon spokesman.

In December, a State Department group headed by American diplomat Ryan Crocker went to northern Iraq to help pull Kurdish and other anti-government forces together.

It is the latest such trip by U.S. officials, but several occurred earlier and they probably will recur, said a U.S. official, speaking on condition of anonymity.

Secretary of Defense Donald H. Rumsfeld said Sunday on a television talk show that ``very small numbers'' of Americans from various departments were involved.

Late last year, a bipartisan group of nine members of Congress asked Bush to support Iraqi opposition forces with humanitarian aid, information gathering and military training.

The lawmakers said in a letter to the president that U.S. efforts to replace Saddam would not succeed without the help of allies on the ground inside Iraq. They suggested support should be directed to the London-based Iraqi National Congress, the umbrella organization for all major groups opposed to Saddam.

Ignoring lawmakers' wishes, previous administrations have denied U.S. assistance for the INC to carry out operations inside Iraq.

The Bush administration, however, has provided money for an information-collecting program and also paid for humanitarian aid offices in New York and Washington. The group has provided no plan for distributing the assistance.

Under a $97 million Congressional outlay, some nonlethal training has been provided. In all, the Iraqi National Congress has received $12.4 million since 1998.

On the Net: State Department's Iraq page: http://www.state.gov/p/nea/ci/c3212.htm