"Gaps in insurance coverage against acts of terrorism weaken our economy and pose a very real threat to our homeland security," said Martin DePoy, vice president of government relations with the Washington-based National Association of Real Estate Investment Trusts.

"Unfortunately, the insurance industry has neither the capacity nor the willingness to underwrite comprehensive terrorism coverage at this point in time," he said.

Some 26 associations and individual companies are members of the new coalition, including the National Association of Manufacturers, the National Association of Realtors, the National Association of Home Builders, the U.S. Chamber of Commerce, and the National Football League.

There are no insurance industry representatives.

Mr. DePoy said that the coalition is concerned that unless Congress steps in, terrorism insurance will be available only at prohibitively high rates, or not available at all.

"The economic impact of further terrorist attacks on the businesses represented by the coalition members is immeasurable," he said. "Without insurance, it could be catastrophic."

Mr. DePoy said the coalition will ask Congress to craft a plan that will give insurers the means to provide comprehensive coverage.

"At this critical time in the nation's history," he said, "a dysfunctional insurance system could jeopardize our economic recovery and weaken our homeland security."