The U.S. Department of Homeland Security said on Friday it awarded $1.16 billion in contracts to three companies to develop equipment to scan cargo at border cities for nuclear weapons material.

New York and New Jersey will get some of the first 80 devices, which were ordered immediately and will arrive this autumn, said Jarrod Agen, a Homeland Security spokesman.

Agen said the award was not in response to a disclosure last week of a foreign-based plot to stage a suicide bombing of a New York rail tunnel later this year. We started this months ago, he said. We know that the New York-New Jersey region represents one of the nation's highest-risk areas.

The contracts, for a program known as the advanced spectroscopic portal, were awarded to Raytheon Co., Thermo Electron Corp. and Canberra Industries.

The equipment will be used by U.S. Customs and Border Protection officials to more clearly distinguish between naturally occurring radioactive materials and highly enriched uranium or weapons grade plutonium.

The single biggest threat we worry about in terms of protecting this country and securing the homeland is the threat of a weapon of mass destruction, and at the very top of the scale is a nuclear device or a radiological device, Homeland Security Secretary Michael Chertoff told reporters.

New York City Mayor Michael Bloomberg, who has assailed Homeland Security for giving millions of dollars to other states that he says face much less risk from attacks, thanked Chertoff.

As I have often said, the number of containers that go in and out of America by truck, airplane and ship is so great that we could never physically inspect every single one and still have a functioning economy, Bloomberg said.

Officials did not give the specific breakdown of the contract award but said it was divided about equally between the three companies.

Some of the first 80 devices also will be sent to a test site in Nevada, and other secondary locations around the nation, Agen said. Secondary sites are ones that check cargo after it has been examined at primary locations, he explained.

The new program will create a next generation of radiation technology to help avoid false positives and more quickly intercept a possible radiological or nuclear bomb.

The contract covers a base year of mainly research and development, followed by four one-year options by the department.

The companies will supply a total of 1,400 radiation detection machines that will be installed at ports of entry and will be used to screen cargo containers and truck traffic.

(Additional reporting by Joan Gralla)