New ads appearing in the U.S. call on tourists to boycott Alberta until the provincial government halts the expansion of the oilsands and opts for "clean energy alternatives." But the province's government is firing back.

On Wednesday, billboards carrying the ads began appearing in Seattle, Portland, Ore., Denver and Minneapolis.

One of the billboards reads "Alberta: the Other Oil Disaster" and features two images of birds coated in oil. One of the birds was purportedly from the Gulf of Mexico, following the oil spill there; the other was said to be from a tailings pond in northern Alberta.

Similar ads will be appearing on Google and on tourism websites. There is also an online video that intersperses images of Lake Louise with others from the oilsands tailings ponds.

San Francisco-based group Corporate Ethics International launched the campaign, dubbed "Rethink Alberta," which it plans to bring to the United Kingdom in two weeks.

Alberta Premier Ed Stelmach reacted heatedly to the campaign.

"This, of course, does anger me to a large degree because it's an attack on about 100,000 Albertans whose lives depend on the tourism industry," Stelmach said.

The province's Energy Minister Roger Liepert called the ads "almost slanderous."

"We must admit that we have to do a better job of ensuring that this propaganda doesn't seep into the minds of the public," Liepert told CTV News Channel.

"The facts as they lay them out are absolutely wrong," he said. "It's quite disgusting."

Liepert added that the Alberta government may respond by launching its own ad campaign to counter the group's messages.

A website created as part of the campaign asks visitors to pledge not to visit the province until the Alberta government stops the oilsands from expanding, embraces "clean energy alternatives" and ceases "spending millions of dollars on public relations campaigns designed to keep the United States addicted to dirty Tar Sands oil."

Michael Marx, executive director of Corporate Ethics International, said he expected that provincial authorities would react angrily because the Alberta government has invested so much money building its brand internationally.

"We think the Alberta government has been pretty arrogant in ignoring the concerns of environmental groups in the U.S., in Europe and in Canada, as well as First Nations, and that it's been deceptive in its public relations in claiming that they're greening the tarsands," Marx said.

"We felt like we needed to be more aggressive in calling the government out."

He added that his group doesn't wish to harm tourism businesses but hopes they will get involved in oilsands issues.

"Ultimately we think that the tarsands industry, by contributing to global warming, actually endangers the tourist industry," he said.

Another campaign has been growing in the U.S. that hopes to block TransCanada from building the Keystone XL pipeline that would carry crude from Alberta to refineries in Texas. Henry Waxman, a prominent congressman, and 50 other legislators stated their opposition to the project.

Last month, Syncrude Canada was found guilty on environmental charges stemming from the 2008 death of 1,600 ducks in a tailings pond.

The Alberta government recently took out a half-page ad in the Washington post that stated "a good neighbour lends you a cup of sugar. A great neighbour supplies you with 1.4 million barrels of oil per day."

With a report from CTV's Janet Dirks and files from The Canadian Press