Just one day after a U.S. company launched its anti-oilsands campaign against Alberta, it is admitting to an error.

The ad campaign urges tourists to "rethink" any travels plans destined for Alberta. San Francisco-based Corporate Ethics International calls Alberta an "environmentally unfriendly place" due to its oilsands.

A video on the campaign's website, rethinkalberta.com, states: "The Tarsands are destroying an area twice the size of England."

But now the executive director of the company behind the ads says it made a mistake.

"We did make a mistake -- it's actually a size a little larger than one England and we're going to go back into the studio and make that change," said Michael Marx.

The ads depict phrases such as, "Alberta: the Other Oil Disaster", and show images of oil-covered birds. The billboards are going up in cities such as Seattle, Portland, Denver and Minneapolis. The campaign is said to be expanding to the United Kingdom in a couple of weeks.

But the provincial government is firing back. A spokesperson for the Premier's Office says even with the company's error adjustment, the ads are still far off from the truth.

"The area that's actually being disturbed is about two-tenths of one per cent of that," said Jerry Bellikka. "It's no where near the size of England -- in fact it's not even the size of London."

Corporate Ethics International is standing behind its figures. It names Alberta university professors, the Pembina Institute and environmental groups as sources.

The company's video also states, "Every day the Tarsands leak nearly three million gallons of poison into the water system."

Corporate Ethics International defends this statistic by saying it came from Environment Canada. And in a surprising twist, the province doesn't disagree. But the Premier's Office does insist the reason emission rates are on the climb is because the province is pumping out more oil to meet market demands.

"Yes the volume is growing, but the intensity is shrinking," said Bellikka.

Marx says in the end, it's the amount of emissions that count.

Alberta's Energy Minister Ron Liepert called the ads "disgusting" and feels the campaign is "over the top".

"It's frankly almost slanderous," he told CTV News Wednesday. "If a group like this was saying something about a corporation or an individual they would find themselves in court quickly."

The Wildrose Alliance says it is willing to reach out to its political opponents in an attempt to unite against the attacks on the province.

"We cannot stop people from spreading misinformation about our great province, the energy industry or the real state of Alberta's environment. But we can come together to show Albertans that we take these attacks seriously and we will respond in the best interests of the people we all represent," said Wildrose Alliance Leader Danielle Smith

From July 16-20, the province is set to host the Pacific Northwest Economic Region for an energy summit. More than 500 delegates from Western Canada and the United States will meet to talk about energy issues.

And the Wildrose Alliance believes the timing would be perfect to counter what it calls "the misinformation and attacks that continue against our province and energy industry."

Smith says the party has reached out to the PC Party, the Alberta Liberals, the Alberta New Democrats and Independent MLA Dave Taylor.

So far, the Premier's Office says it is not considering the partnership at this time.

With files from Jessica Earle