[an error occurred while processing this directive]"Today I have reached a difficult personal decision. I will not be a candidate for Speaker of the 106th Congress," Mr Gingrich said.

He informed senior Republicans of his decision in a conference call from his Georgia home.

He did not say whether he also intended to resign as a congressman but a senior aide is quoted as saying it was "highly unlikely he will serve out his full term."

Tom Carver: Newt Gingrich took the blame for election failure

The Republican leader has taken much of the blame for the party's unexpectedly lacklustre performance in the elections, the worst performance in 34 years by a party not in control of the White House.

President Clinton, on a visit to his home state of Arkansas, paid tribute to a man he called "a worthy adversary".

All smiles: Newt Gingrich and his wife Marianne face reporters shortly after the announcement

In a written statement the president said he appreciated "those times we were able to work together in the national interest".

Republican politicians have also paid tribute while saying that it was time for a change.

The Chairman of the Republican National Committee, Jim Nicholson, said: "Newt Gingrich has been a visionary figure in our party, one who has transformed American politics.

"His announcement today was a magnanimous gesture, typical of the man."

The BBC's Washington Correspondent, Tom Carver, says it will take some time for the Republican Party to find a replacement for Mr Gingrich, which can only help President Clinton to restore his own reputation and credibility.

Challenge

Earlier senior Republican congressman Bob Livingston announced his intention to challenge Mr Gingrich for the Speaker's post.

Bob Livingston: "We want politicians with ideas that work"

Mr Livingston, who is chairman of the powerful appropriations committee of the House, said he wanted to change the party's management style.

Republicans had expected considerable gains in the House but found their majority narrowed, despite the cloud of the Monica Lewinsky scandal hanging over the Democrats.

Bob Livingston: Experienced

In the end the Republican majority in the House was reduced to five.

Mr Gingrich led the so-called Republican revolution which swept the party into power in 1994, giving them their first majority in the House of Representatives since 1954.

But many Republicans now accuse Mr Gingrich of losing sight of their tax-cutting agenda and underestimating public weariness with the Monica Lewinsky scandal.

"We didn't understand that people would frankly just get fed up with the existence of the topic," Mr Gingrich admitted.

The party is said to be deeply divided with moderates and extreme right-wingers drawing different lessons from the mid-term failure. But on all sides there seems to be dissatisfaction with the current leadership.

Republican House members are due to meet on 18 November to choose their new leadership team.