WASHINGTON (AP) — The U.S. campaign against terrorism will not completely eradicate it, Defense Secretary Donald H. Rumsfeld says.

Although President Bush has vowed repeatedly to "rid the world of evildoers," Rumsfeld said Monday that U.S. goals were more modest.

"The only way we can defend the way of life of Americans, free people, is to not think you can defend against every conceivable terrorist everywhere in the world," Rumsfeld said. Eliminating terrorism, he added, is "setting a threshold that is too high." 0 Bush has said repeatedly that his intention was to "rout out and whip terrorism."

Rumsfeld spoke at a news conference Monday announcing home mortgage interest rate cuts for National Guard and Reserve soldiers called to active duty. It was part of a package of measures aimed at easing the burden on the home front for troops joining the anti-terrorism battle.

The Education Department ordered lenders to postpone the student loan payments of troops called to active duty since the Sept. 11 terrorist attacks. It also encouraged schools to refund tuition or give comparable credit to students forced to withdraw from school because of military obligations.

Bush on Monday formally notified Congress that he had ordered "various combat equipped" and combat support forces to the Middle East and Southwest Asia in response to the terrorist attacks.

"It is likely that the American campaign against terrorism will be a lengthy one," Bush wrote in a report to satisfy the War Powers Resolution that obliges a president to notify lawmakers when military force is used.

Bush added that he may have to send other military forces to other countries during the campaign.

Rumsfeld stressed that the administration still was considering a range of options in response to the attacks on the World Trade Center and the Pentagon. He said the aim was "to create a situation where it becomes in people's interest to not support terrorists or terrorist networks and, where they exist, to attempt to make life uncomfortable for them, and expel them or turn them in."

Rumsfeld did not comment on a weekend report by the Russian Interfax news agency that three U.S. Air Force transport planes had arrived in Uzbekistan carrying about 200 U.S. troops and reconnaissance equipment. Uzbekistan shares a border with northern Afghanistan, where Osama bin Laden, the Bush administration's leading suspect in the terror attacks, is believed to be hiding.

An official in Pakistan said the United States probably would be granted access to at least four airfields in Pakistan. Three were in the southwestern part of the country and one in the northwest, and all were near Pakistan's border with Afghanistan.

Rumsfeld declined to say whether the administration planned to verthrow the Taliban religious militia that rules most of Afghanistan.

"We're intent on altering behavior," he said.

As the U.S. military buildup continued, the Air Force announced that it was invoking "stop loss" authority, preventing any member from retiring or otherwise leaving the service for at least 30 days. Those who already have approval to leave or retire before Oct. 1 are exempt, as are people who must retire due to disability.

Rumsfeld and Mel Martinez, the secretary of housing and urban development, said Reserves and National Guardsmen who are called up and who have home mortgp with Federal Housing Authority-approved lenders will have their rates cut to a maximum of 6 percent for one year. It also gives these military members more protection against foreclosure on their home loans, and renters more protection against eviction.

About 10,000 members of the National Guard and Reserves have been called to active duty since the terrorist attacks, and Rumsfeld has clearance from the White House to call as many as 50,000.

Martinez said he also is encouraging — but cannot require — mortgage lenders to postpone principal payments for all servicemen and women during their tour of active duty. Once payments are resumed, they would increase so the loan would still be paid off by the date specified in the original mortgage.