Though Mr Bush did not name anyone, his remarks on Thursday were widely seen as a rebuke to Democratic Senator Barack Obama, who has advocated greater engagement with countries such as Iran and Syria.

The comments triggered an angry backlash in the United States, as Democrats accused Mr Bush of breaching protocol by playing partisan politics overseas, while allies also said he had transgressed by launching a partisan attack on foreign soil.

'Some seem to believe that we should negotiate with the terrorists and radicals, as if some ingenious argument will persuade them they have been wrong all along,' Mr Bush had told the Israeli parliament.

'We have heard this foolish delusion before.

'We have an obligation to call this what it is - the false comfort of appeasement, which has been repeatedly discredited by history,' he said, drawing parallels with the 1930s capitulation to the Nazis.

The White House denied the comments directly targeted Mr Obama. But the Illinois Senator, who is looking to eliminate Mrs Hillary Clinton from the Democratic race to succeed Mr Bush, waded into the row.

'It is sad that President Bush would use a speech to the Knesset on the 60th anniversary of Israel's independence to launch a false political attack,' said Mr Obama in a pointed e-mail response.

'Instead of tough talk and no action, we need to do what Kennedy, Nixon and Reagan did and use all elements of American power - including tough, principled, and direct diplomacy - to pressure countries like Iran and Syria.'

And his rival Mrs Clinton, who had earlier threatened to 'obliterate' Iran if it should attack Israel, took up the cudgels as well, saying: 'President Bush's comparison of any Democrat to Nazi appeasers is offensive and outrageous, especially in the light of his failures in foreign policy. This is the kind of statement that has no place in any presidential address.'

Mr Obama said in a Democratic presidential debate last July that he would be willing to hold talks, without preconditions, with the leaders of Iran, Syria, North Korea, Venezuela and Cuba.

But he also said he would take no option off the table to stop Iran from using or obtaining nuclear weapons.

Senator Joseph Biden was one of many Democrats who sprang to Mr Obama's defence, accusing the Bush administration of hypocritically pursuing talks with North Korea and, in the past, Libya.

'Under George Bush, the Middle East has become more dangerous - the US and our allies, including Israel, are less secure. His policy has been an abject failure.

'For him to call those who rightly see the need for change appeasers is truly delusional. And for him to do it from abroad is truly disgraceful,' said Mr Biden, who is the chairman of the Senate Foreign Relations Committee.

The presumptive Republican nominee for president, Senator John McCain, tried to turn the spat to his advantage, saying Mr Obama had made a 'serious' error in offering to talk to Iranian President Mahmoud Ahmadinejad, a week after suggesting that Mr Obama was the favoured candidate of Hamas.

'It shows naivety and inexperience and lack of judgment to say he wants to sit down across the table from an individual who leads a country that says that Israel is a stinking corpse,' Mr McCain said.

Thursday's episode placed Mr Bush squarely in one of the most divisive debates of the campaign to succeed him, as Republicans try to portray Mr Obama, the likely Democratic nominee, as weak in the fight against terrorism.

It also underscored what would be an aggressive effort by Mr Bush to use his presidential platform to influence the presidential race.

NEW YORK TIMES, AGENCE FRANCE-PRESSE