OTTAWA - Stephen Harper finally said sorry today as he attempts to put controversy behind him and get his campaign message back on track.

The prime minister apologized for people being booted from Conservative campaign events on suspicion they supported rival parties or groups.

"If anybody is kept out of any of our events that's there to hear our message, then we obviously apologize to them," he said during a stop in Vaughan, Ont. "Our interest is in having as many people out to hear our message as we can."

The three-day-old controversy was stoked Wednesday by two new revelations:

-- The RCMP admitted that some Mounties helped the Tories eject people, and reminded its officers that their job is to guard leaders, not serve political parties.

-- The Conservatives allowed a supporter facing fraud-related charges to volunteer on their campaign — and get a plum seat behind Harper at a rally last week.

Harper turned his attention to tax relief, hoping that will help win crucial votes in suburban Toronto.

He promised to double the amount that can be put in Tax Free Savings Accounts to $10,000 a year. But there's a catch — the measure wouldn't start until the federal budget is balanced, projected for 2015-16.

The accounts allow people to collect tax-free interest and the Tories say 4.7 million Canadians are believed to have accounts. But a study done last fall said many Canadians remain confused about how the program works.

Harper made the announcement with MP Julian Fantino, who won the Vaughan riding in a byelection last fall. The Conservatives are eager to hold the seat, which was a steal from the Liberals.

Harper finishes his day with a rally in Hamilton, just a dozen or so blocks from a competing town hall meeting featuring Liberal Leader Michael Ignatieff.

Ignatieff started his day at a seniors' residence in Laval, Que., where he outlined promises to improve the pension system.

He had troubles of his own, condemning remarks by a Liberal candidate in Alberta who suggested not all types of sexual assault should result in jail time. John Reilly, the candidate in the riding of Wild Rose and a former provincial court judge, had earlier apologized for the comments.

Ignatieff stopped short of banishing Reilly, citing his long and distinguished public record.

On Wednesday, Ignatieff dumped a candidate in a no-hope northern Quebec riding who had made derogatory remarks about natives, Muslims and gays.

NDP Leader Jack Layton is in B.C. today, and Green party Leader Elizabeth May made a rare foray out of the Vancouver Island riding where she's running to formally launch the Green platform in Toronto.