In an historic moment, former White House adviser Tom Ridge was sworn in Friday as secretary of the newly-created Department of Homeland Security, becoming the 15th member of President Bush's Cabinet.

"Today marks another step in this country's effort to secure the homeland," Ridge said to reporters Friday afternoon.

"[President Bush has] given me an opportunity to work with him and an extraordinary team that he's assembled during these critical times in America's history," Ridge added. "And I'm very proud and grateful for that opportunity."

Vice President Dick Cheney swore in Ridge, who left his job as governor of Pennsylvania to become Bush's homeland security adviser after the Sept. 11, 2001, terrorist attacks, in a brief White House ceremony.

"I knew immediately that Tom was the right man for the assignment," Bush said after the ceremony. "He is a person of integrity and a person of good judgment. He has done an outstanding job and earned the gratitude of the American people."

"The American people can be certain that the mission of homeland security will be carried out with focus and resolve with the resources that the task requires, and the American people can know as well that the department is under the command of a superb leader who has my confidence," the president added.

Ridge promised that he and the 170,000 people in his department would "do everything we can to prevent a terrorist attack, to reduce our vulnerability, to prepare for an attack, to respond as quickly as possible, to do it to our very best ability every single day."

While facing ample commendations by senators during his confirmation hearing one week ago, Ridge now inherits instant headaches along with the $38 billion agency.

Some budget analysts, like the Brookings Institution, say Ridge's new department should have been funded at a 25 percent higher level to do the job it is supposed to do.

Analysts suspect that upgrading security around power, water and chemical plants and at the nation's ports as well as better equipping police and firefighters and other first responders will cost billions more, which Congress will need to find even as the country faces budget deficits in the $200 billion to $300 billion dollar range.

White House Press Secretary Ari Fleischer said money is just one of the problems Ridge will face.

"The most urgent areas remain the definition of the department — it's the critical infrastructure, it's the border security, it's those type of issues that will continue to be the top priorities, the intelligence analysis — all of the core missions remain their top priorities," Fleischer said.

Ridge faces the task of homeland security just as the United States gears up for war with Iraq, which it is finding a tough sell to other nations.

With such an aggressive stand, many at home fear war will beget more terrorist attacks. The Sept. 11 attacks killed some 3,000 people on U.S. soil and launched the largest reorganization of the federal government since the Defense Department was created in 1947.

The new Department of Homeland Security, which won't be fully active until March 1, will have its own analytical unit to examine intelligence gathered by the CIA, FBI and other agencies seeking to uncover terrorist plots. Bush ordered the new unit into being on Thursday.

The Information Analysis Infrastructure Protection, which will likely be more commonly known as IAIP, will function as the new homeland intelligence arm and will have the same authority as other intelligence agencies.

The president's executive order, signed Thursday night, also officially gives Ridge the power to consult with other Cabinet agency heads, specifically the State, Treasury and Justice Department chiefs, and identify terrorists and their supporters.

The new department also will coordinate with 2 million police, firefighters, medical personnel and other first responders around the country.

Among the agencies moving into the new department are the Secret Service, Coast Guard, Customs Service, Immigration and Naturalization Service, Transportation Security Administration, Federal Emergency Management Agency and other security-related units.

There will be five undersecretaries in charge of border and transportation security, science and technology, first responders, intelligence, and budget and management issues.

On Wednesday, the day the Senate approved Ridge as secretary in a 94-0 vote, former Drug Enforcement Administration head Asa Hutchinson was unanimously approved by the Senate Commerce Committee to become the undersecretary of border and transportation security.

The Senate Governmental Affairs Committee was meeting Friday on the nomination of Gordon England to be the deputy secretary of the department.

Ridge, a Vietnam War hero, six-term congressman and two-term Pennsylvania governor who resigned his job to take over homeland security, is now the 18th person in the line of succession for the presidency, ranking after Anthony Principi, the secretary for the Department of Veterans Affairs.

The department's headquarters will be at a secure office complex, run by the Navy, in northwest Washington.

The site, the Naval District of Washington's Nebraska Avenue Complex, is near the American University campus and a few blocks from Vice President Dick Cheney's residence at the U.S. Naval Observatory.

Ridge becomes the 15th member of Bush's Cabinet, along with the secretaries of the departments of Agriculture, Commerce, Defense, Education, Energy, Health and Human Services, Housing and Urban Development, Interior, Justice, Labor, State, Transportation, Treasury and Veterans Affairs.

Fox News' Wendell Goler and Catherine Herridge and the Associated Press contributed to this report.