QUEBEC - Convinced that a fall election is on the horizon, Bloc Quebecois Leader Gilles Duceppe unveiled his plan Tuesday for a double-barrelled blast against Michael Ignatieff and Stephen Harper.

The sovereigntist party is preparing, for the first time in memory, a two-pronged offensive that will include ads tearing a strip off two adversaries.

That Duceppe has targeted the two big national parties at the same time is the clearest indication yet of how Quebec could become a three-way battlefield in the next election.

Speaking to reporters after a caucus meeting in Quebec City, Duceppe offered a preview of what will be a key campaign theme: that Ignatieff and Harper are identical.

He said both men have thrown their support behind the oilsands, the Iraq war and Ontario's ailing auto sector - but not Quebec's sagging forestry industry.

"In reality, the Liberal leader has the same position as Stephen Harper regarding everything that's essential for Quebec," Duceppe said in a speech that primarily targeted Ignatieff.

"Only the Bloc stands up for the interests of Quebec."

Duceppe showed off a print version of his campaign ads, which feature black-and-white photos of half the faces of Harper and Ignatieff - side by side.

In bold letters, the ad reads: "Two parties, one opinion."

Duceppe said the campaign will also show Quebecers that his two main rivals share the same restrictive vision of the Quebecois nation.

"Mr. Harper said, 'We recognized the nation, it's over.' Mr. Ignatieff said, 'Quebec doesn't need any more powers,' " said Duceppe, who would not reveal the launch dates for the ads.

"Mr. Ignatieff practically denies the existence of the fiscal imbalance. Mr. Harper tells us that it's finished."

After recently touring much of the province, the Bloc leader said he's almost certain that Canadians will head to the polls this fall.

"I've acquired over recent days across Quebec the firm conviction that, barring a major change, there will be an election," said Duceppe, who indicated that his party is battle-ready, having already named candidates in 67 of Quebec's 75 ridings.

"Mr. Ignatieff was clear - he can no longer back away. As for Mr. Harper, he is inflexible and has not given any signs of openness."

The Bloc's campaign strategy this time differs from the last few elections, where Duceppe concentrated either on the Tories or the Liberals and largely ignored the other.

One of the reasons Duceppe's party lost seats in 2006 was it was caught off-guard by the rise of the Tories. After having spent more than a decade exclusively attacking Liberals, it took the Bloc precious campaign days to recalibrate their sights on a new enemy.

The plan suggests the Bloc may feel threatened by the Ignatieff-led Liberal Party.

Leading up to last year's federal election campaign, Duceppe declared that the battle for Quebec would be a dogfight between the Bloc and the Tories.

In many of his campaign speeches he paid little or no attention to the Liberals - then led by Stephane Dion - and even brushed aside questions about a party he concerned a non-threat.

Last week, Ignatieff announced that his party will try to topple the Harper government this fall.

The Liberal leader said the fate of the Conservative minority government is now in the hands of the other parties.

Duceppe's remarks suggest the Tories have only one potential dance partner remaining: NDP Leader Jack Layton.

The government is now showing signs it might be eager to court Layton, announcing that it plans to make changes to Employment Insurance that would benefit long-time workers who've lost their jobs.