The decree - or fatwa - accused Mr Rushdie of blasphemy. It was issued by the late Ayatollah Khomeini more than nine years ago.

Kharrazi: Under pressure from hardliners?

Last month, the Iranian Foreign Minister, Kamal Kharrazi, said his government would not pursue the death threat against Mr Rushdie.

The move led to Britain and Iran deciding to upgrade diplomatic relations and exchange ambassadors.

But Iranian TV has reported that 150 of the 270 members of parliament have signed an open letter stressing the fatwa is irrevocable.

According to Iranian media the letter reads: "We assure Muslims all over the world that nothing except the decrees issued by God and the exalted Imam Khomeni in Iran have any credibility and no-one has the power to follow any other path."

No change on Rushdie

And Mr Kharrazi has also said Iran has not changed its stand on the controversy surrounding Mr Rushdie.

He insisted it was the British Government which decided to normalise ties after accepting Tehran's position on the issue.

Rushdie: Nine years of threat

In remarks quoted by Iranian radio on Saturday, Mr Kharrazi said: "We did not adopt a new position with regard to the apostate Salman Rushdie, and our position remains the same as that which has been repeatedly stated by the Islamic Republic of Iran's officials.

"In fact, it was the British Government which decided to elevate its political relations with Iran to ambassadorial level.

"This itself is further evidence of the just position and power of Iran in the international community."

Last month Iranian President Mohammad Khatami said the Rushdie affair should be considered completely finished.

After talks with British counterpart Robin Cook in New York, Mr Kharrazi said the government would distance itself from a $2.5m bounty placed on Mr Rushdie's head by a radical religious foundation.

Several senior clerics have also vowed that the fatwa will continue to stand, regardless of the government's views.

Three days after Mr Kharrazi's statement in New York an Iranian Foreign Ministry spokesman said the late Ayatollah Khomeini's fatwa against Mr Rushdie could not be revoked.