Mr John McCain, a fervent supporter of the war in Iraq, began a Middle East tour on Sunday encompassing Iraq, Jordan and Israel. -- PHOTO: AFP

Mr McCain, 71, insisted during an official visit in Amman on Tuesday that members of Al-Qaeda in Iraq were slipping into neighbouring Iran and receiving training there before returning to the war-torn country to wreak havoc.

But while President George W. Bush's administration has accused Shiite-majority Iran of training and arming Shiite extremists, it has never made the link with Al-Qaeda in Iraq, which is a Sunni group.

Mr McCain made the gaffe right in the middle of an official visit in the Middle East that was supposed to highlight his knowledge in foreign affairs.

'It's common knowledge and has been reported in the media that Al-Qaeda is going back into Iran and receiving training and are coming back into Iraq. That's well known,' the Vietnam war veteran said.

Pressed by reporters about his allegations, Mr McCain said: 'We continue to be concerned about the Iranians taking Al-Qaeda into Iran and training them and sending them back.' It was only after fellow Senator Joe Lieberman, who was travelling with him, whispered into his ear that Mr McCain corrected himself.

'I am sorry, the Iranians are training extremists, not Al-Qaeda, not Al-Qaeda, I am sorry,' Mr McCain said.

Democrats pounced on Mr McCain's slip-up.

'Just yesterday, we heard Senator McCain confuse Sunni and Shiite, Iran and Al-Qaeda,' Democratic White House hopeful Barack Obama said on Wednesday, using the mistake to criticise Mr McCain's vote authorising the five-year-old war in Iraq.

'Maybe that is why he voted to go to war with a country that had no Al-Qaeda ties,' the senator of Illinois said. 'Maybe that is why he completely fails to understand that the war in Iraq has done more to embolden America's enemies than any strategic choice that we have made in decades.' 'Above all, the war in Iraq has emboldened Al-Qaeda, whose recruitment has jumped and whose leadership enjoys a safe-haven in Pakistan - a thousand miles from Iraq.'

Recent polls have suggested a majority of Americans view Mr McCain as the candidate best suited to tackle an international crisis.

Democratic party spokeswoman Karen Finney seized on the opportunity to point out Mr McCain's mixup had revealed his foreign policy incompetence and showed he 'ignore(d) the facts on the ground.' 'After eight years of the Bush administration's incompetence in Iraq, McCain's comments don't give the American people a reason to believe that he can be trusted to offer a clear way forward,' Ms Finney said in a statement.

Mr McCain, a fervent supporter of the war in Iraq, began a Middle East tour on Sunday encompassing Iraq, Jordan and Israel. The veteran Arizona senator is expected later this week in London and Paris.

Mr McCain's campaign insisted that the slip does not represent the breadth of his foreign policy knowledge and accused Democrats of waging a politicized attack aimed at capitalising on a minor mistake.

Asked about the confusion on NBC News, Mr McCain said: 'I corrected it, my comment, immediately. To think that I would have some lack of knowledge about Sunni and Shiite after my eighth visit and my deep involvement in this issue is a bit ludicrous.' He added: 'I just simply misspoke when I said Al-Qaeda, but they (Iranians) are training extremists and they are sending the most lethal kinds of devices in (to Iraq) that are killing Americans. That's what we should care about.' Anti-war Democrats shuddered over Mr McCain's antics last year in April.

Asked by a hawkish supporter when the United States would 'send an airmail message to Iran,' Mr McCain responded: 'You know that old Beach Boys song, Bomb Iran?' Then, to the tune of the song 'Barbara Ann,' he sang: 'Bomb bomb bomb, bomb bomb Iran.' -- AFP