Australia's prime minister has condemned members of his own party for distributing leaflets implying the Labor opposition supports terrorism.
Mr Howard (R) is trailing Mr Rudd in opinion polls
John Howard, who trails Labor's Kevin Rudd in opinion polls ahead of a Saturday's general election, said the Liberal Party had not authorised them.
The flyers purported to be from an Islamic group thanking Labor for its sympathy for the Bali bombers.
Two Liberal activists have been expelled from the party.
The leaflets were distributed in the Sydney constituency of Lyndsay - a marginal seat in a keenly fought election campaign.
Two local activists - Gary Clark and Greg Chijoff - admitted involvement and issued statements apologising for the leaflet campaign.
It was not immediately clear if they were the two activists who had been expelled.
Mr Clark is married to current Liberal MP for Lyndsay, Jackie Kelly. Mr Chijoff's wife is her would-be Liberal successor, Karen Chijoff.
Mr Howard said he accepted the men's assertion that neither of their wives had known of the leaflet campaign.
The BBC's Nick Bryant, in Sydney, says that this kind of scandal is just about the last thing Mr Howard's beleaguered party needs.
Party activists were caught distributing the leaflets on Wednesday.
They purported to be from the Islamic Australia Federation - a made-up organisation - and referred to the men imprisoned for the 2002 nightclub bomb attacks in Bali, which left more than 200 people dead, many of them Australians.
"We gratefully acknowledge Labor's support to forgive our Muslim brothers who have been unjustly sentenced to death for the Bali bombings," it said.
Labor supported the building of new mosques, the leaflets added, thanking the party for backing the entry of controversial cleric Sheikh Taj el-Din al-Hilali - who likened scantily-clad women to uncovered meat.
'Unfair and dishonest'
Mr Howard said that this type of material should never have been distributed.
"It was not authorised by the Liberal Party, it is no part of our campaign, it was wrong and unfair and dishonest for any pamphlet to be distributed suggesting that the Labor Party was sympathetic to the Bali bombers," he said.
Mr Rudd has urged the Liberals to clarify who knew about the leaflets.
"This says everything about the desperate and desperation politics on the part of the Liberal Party on the eve of the election," he told Australian radio.
The issue has been referred to the Australian Electoral Commission, and Labor has asked it to investigate whether the authors acted illegally by appealing to anti-Muslim sentiment.
The president of the Australian Federation of Islamic Councils, Ikebal Patel, told ABC radio that while election campaigning to date had been "fairly good" on the issue of migration, the use of the flyers was "quite despicable".