The move is being seen as an attempt to head off a damaging trade war.

The concessions have been welcomed by the Japanese government, which had set a deadline of the end of August to decide on what counter measures to take.

The European Union has said it would appraise the US' softened stance on Friday, though it has until late September to decide whether to slap retaliatory sanctions on US products.

The tariffs were imposed in March in an attempt to protect the US steel industry.

But now nearly one quarter of imports covered by the original order are exempt from the tariffs.

Japan's deadline stands

A Japanese trade ministry official said about 70% of Japanese steel exports now fell outside the US tariffs net.

We are crossing the threshold of whether the tariff will do the job that the administration and the industry agreed needed to be done

Gary Hubbard United Steel Workers of America Union

But, he added: "About 650,000 tonnes will still be affected and we are still assessing the matter."

The trade minister has reportedly said talks with the US are due to continue.

The US has denied that its concessions were influenced by threats of retaliation from the European Union and Japan.

But US steelmakers already fear that the tariffs will no longer be effective.

No more exemptions?

The administration of US President George W Bush said the latest group of exclusions was the seventh and final group to be granted exemptions from the tariffs this year.

But it said it would in November allow steel customers to lodge requests for further exclusions.

Since the beginning of June, the US has exempted a total of 727 products.

The products covered in this latest group covered a broad range of steel products, from plate and hot-rolled to tin mill and stainless.

Conflicting concerns

US steel producers have been worried that too many exclusions would undermine the effectiveness of the tariffs.

Nancy Gravatt, a spokeswoman for the American Iron and Steel Institute, said steel producers were "disappointed at the large number of exclusions granted over industry objections".

"We are crossing the threshold of whether the tariff will do the job that the administration and the industry agreed needed to be done," Gary Hubbard, a spokesman for the United Steel Workers of America Union, said.

But the country's steel-consuming companies have complained that the tariffs have forced US steel prices to rise higher than expected.

Balancing act

The US Trade Representative's office and the Commerce Department said the latest exclusions followed consultations with US steel consumers and producers, and foreign producers.

"This is part of the administration's objective of providing relief only where needed in the steel industry, and to avoid burdening US steel consumers," the statement said.

The full list of exclusions is on the US Trade Representative's web site (see link above).