Communities facing greater risks will receive a bigger share of federal grants this year to counter terrorism and other threats, the head of the Homeland Security Department said Tuesday as he announced that nearly four dozen metropolitan areas will be eligible.

Overall, $756 million will be distributed under the urban area security initiative, a cut from $855 million that Congress provided last year, the department said. Some congressional critics have complained that in the past, the program has given too much money to communities that seem to face smaller risks of attacks.

The agency, saying it was revamping the way the assistance is distributed, said 35 metropolitan areas will be eligible for the money this year, but only if they show they will use the money wisely.

Some of the areas eligible include Chicago, Phoenix, Denver, Washington, D.C., Miami, Atlanta, Indianapolis, Baton Rouge, New Orleans, Boston, Detroit, Las Vegas, Dallas and Philadelphia. The only new metropolitan area added this year was Memphis, Tenn.

Another eleven areas that previously received money under the program will still be eligible, but were told they may be dropped next year unless they can show a compelling need and a sound plan for using their share of the $765 million.

"We are taking a giant step forward in implenting this risk-based strategy," Homeland Security chief Michael Chertoff told reporters.

He added later that the grants were "not party favors to be distributed as widely as possible."

Officials said the department will announce the funds each community gets in June.

The eligible communities were in 29 states, plus the District of Columbia.

The change, outlined in departmental documents sent to state and local officials, addresses both the destruction and lack of preparedness seen during Hurricane Katrina.

It also reflects Chertoff's efforts to give his department an all-hazards mission, even though it was created as a direct result of the Sept. 11, 2001, terror attacks.

Other grants distributed by the Homeland Security Department have pitted highly populated areas against rural regions, and been criticized for provided more money per capita to some sparsely populated states.

In past years, the grants generally have gone to the nation's 50 largest cities for terror-related security measures. This year, however, cities that risk being hit by a natural disaster or a health crisis would also be eligible, according to the documents.

"In light of several major new national planning priorities, which address such issues as pandemic influenza and the aftermath of Hurricane Katrina, the allowable scope of (grant) activities (include) catastrophic events -- provided that these activities also build capabilities that relate to terrorism," according to a 203-page Homeland Security plan for state and local officials.

"For example, mass evacuation planning supports terrorism preparedness but also other types of catastrophic events," it said. "Planning for pandemic influenza and linking that effort to a larger bioterrorism preparedness effort offers another example. Grantees must demonstrate the dual-use nature of any activities implemented under this program that are not explicitly focused on terrorism preparedness."

Homeland Security spokesman Russ Knocke would not comment on which cities will be eligible for grants this year. Aides to lawmakers who oversee Homeland Security said they received very vague briefings by department officials on the changes, but weren't told which cities would be eligible.

Calls to city officials around the country and to the U.S. Conference of Mayors for comment were not immediately returned.

A senior Homeland Security official, speaking only on condition of anonymity because the plan isn't public yet, said the new formula uses highly detailed data -- down to an area's ZIP code -- to determine the most vulnerable communities.

It also looks at daily and event-driven commuter populations within cities, and for the first time ranks local infrastructure by risk -- drawing distinctions, for example, between a nuclear power plant and a subway system, the official said.

In another shift, the cities will not know how much money they will receive when their eligibility is announced. Their grants will be determined later based on applications detailing how they planned to spend the money, officials said.