OTTAWA - An incensed Stockwell Day issued an open letter Friday accusing rival Grant Hill of crossing the line in an ongoing leadership spat over backroom deals.

In an eight-paragraph missive addressed "Dear Grant," Day blasts his friend and colleague for what he called a personal attack on his integrity. "While the emotions of a leadership race can lead to strong rhetoric, your comments crossed the line," the letter said. "I find these attacks hurtful not only to me but to our party, especially in light of the fact that you and I have worked closely together as colleagues and friends."

The letter is the latest instalment in a week-long battle in which Day accused his chief leadership rival, Stephen Harper, of misleading the public while meeting secretly with Hill to cook a deal on unity with the federal Conservatives.

The deal, which fell through last weekend according to Hill and Harper strategists, would have seen Hill drop out of the race in exchange for Harper softening his stance against unification with the Tories.

Hill then accused Day of hypocrisy, saying Day's campaign team had approached Hill's team seeking a similar deal on the second ballot.

Day's letter denies Hill's assertions that Day did not tell the truth about the approach.

"You know full well that at no point did I, or any of my supporters, offer any deal in exchange for your dropping out of the race."

Tom Jarmyn, Hill's campaign manager, dismissed Day's letter, calling it a ploy to resurrect Day's beef with Harper.

"It's an effort to revive interest to get the media to come after Stephen Harper on the point," he said, noting the first four paragraphs of the eight-paragraph letter refer more to Harper than to Hill.

"That's the only conclusion I can really draw on it."

Jarmyn added his staff never said a deal had been reached with Day.

"Yes, there was no deal offered, but the fact is MPs from his team, members of his team were calling us and saying, 'would you support us on the second ballot, what do we have to do?"' he said. "And that is what happens (in a leadership race)."

Day also criticized Hill for fostering an escalating war of words he says will tarnish the party's image further.

"Our members have had enough of the internal fighting in our party and the personal attacks between our MPs," the letter says. "We all know that these types of personal attacks have a negative effect on our party."

Eric Duhaime, Day's spokesman, said Friday the letter was issued to set the record straight.

"Those were strong words and we just wanted to bring it to a close," he said.