The library is the biggest in the world

The move means Scottish literature will no longer have its own section in the world's biggest library.

Poet Liz Lochhead said any Scottish writer would be "appalled" by the decision.

A spokesman for the library said it would be reconsidering the controversial decision.

Culture Minister Linda Fabiani pledged to raise the matter with the US Congress.

Under the new rules Scottish Literature and more than 40 Scottish subjects are to be grouped under three headings.

It just seems crazy that they have assumed English means British

Liz Lochhead

They include English Literature - Scottish Authors, Dialect Literature - Scottish, and Scotland - Literatures.

For example, the classic novel The Thirty Nine Steps by Scottish author John Buchan which will now be listed under Adventure Stories - English.

And Scottish science fiction will become Science Fiction - English, while difference between genres of Scottish poetry will disappear.

It is feared that the influence of the Washington-based library will see other libraries around the globe follow suit.

Ms Lochhead, Glasgow's Poet Laureate, said the move was caused by "ignorance" and accused the library of "cultural imperialism."

She told BBC Scotland: "I can't see how it can be helpful to categorise Robert Louis Stevenson as an English author when he clearly is not.

'Cultural differences'

"It just seems crazy that they have assumed English means British. It is a huge piece of cultural imperialism. It must be out of ignorance, which is appalling in this day and age.

"The point is America is the most culturally powerful country in the world and it is hugely damaging not just to Scots but to Welsh and Northern Irish writers."

She rejected arguments that the new classifications were based on the language the authors were writing in, and pointed out: "Can they claim Mark Twain is an English author? Of course not."

Best selling crime writer Ian Rankin said the move failed to recognise the cultural differences that exist between the countries of the United Kingdom.

Culture Minister Ms Fabiani said: "This change has been vigorously resisted by the National Library of Scotland and they have been in touch with the Library of Congress to request reconsideration.

"While this is ultimately a decision for authorities in the USA, this government believes that Scottish Literature is quite distinctive from English Literature and should be recognised as such.

"I shall also be raising this issue directly with congressmen early in the New Year."