The Bush administration is proposing a plan to have taxpayers cover most of the losses that insurance companies would suffer in future terrorist attacks, officials said Saturday.

U.S. insurers estimate that property claims from the Sept. 11 terrorist attacks could total as much as $40 billion.

The industry, one of the biggest donors to lawmakers' campaigns, is not asking for a bailout like the $15 billion rescue package Congress quickly produced for the ailing airline industry. Insurance companies say they can handle current claims.

Instead, they are seeking government help in covering potentially huge and unmanageable costs from future terrorist acts.

Major reinsurance companies, which assume part of the risk covered by primary insurers, already have said they will not renew terrorism coverage after Dec. 31. Without that coverage, insurance companies would have to take on all the risk themselves, and industry executives say that could prompt them to just quit writing policies providing coverage for terrorism.

Industry executives say that could be devastating to the economy, as most lenders require insurance to finance real estate, plant expansion and other projects. They also argue that, since most reinsurance policies expire on Jan. 1, speedy action is essential.

The Bush administration proposal would divide the costs of property claims from terrorist attacks between the government and the industry, with taxpayers picking up about 80 percent of the tab and leaving the rest for insurers, said an administration official, who spoke on condition of anonymity.

The administration proposal also would limit the government's liability to three years, the official said.

The administration views its proposal as an alternative to legislation drafted by lawmakers from both parties in Congress at the behest of the insurance industry. The industry plan recommends a new government-backed insurance company that would manage a pool of premiums and payouts for terrorism policies. Once losses exceeded the amount of money in the pool, the government would cover the difference — which could total much more than taxpayers stand to pay under the Bush administration proposal.

The administration is wary of the industry approach, fearing the creation of a new federal bureaucracy that is insensitive to costs.

Administration officials expect to take the still-being-formulated ideas to Capitol Hill next week, as a starting point for negotiations with lawmakers and the industry, the official said. Another official, also speaking on condition of anonymity, said the administration had agreed that the industry needed some kind of safety net.

Spokesmen for key lawmakers on Capitol Hill did not return calls for comment Saturday. Representatives for large U.S. insurers could not be reached either, but they have said they were open to a plan that would help calm insurance markets.

The wrangling does not affect the life insurance business, which is expected to pay between $2 billion and $5 billion on individuals' policies.