The government withdrew support of Edmonton's bid for the EXPO 2017 because of the cost of protecting Alberta's oilsands, says federal Public Works Minister Rona Ambrose.

A day after Mayor Stephen Mandel ripped into the federal government for withdrawing support of Edmonton’s EXPO 2017 bid, Ambrose cited rocketing security costs.

"The actual security costs associated with a 90-day event like this in the heart of oilsands country is one we needed to take very seriously."

Ambrose pegged the tab to be at least $1 billion.

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Public Works Minister Rona Ambrose cited security costs in the federal government's decision not to support Edmonton's EXPO 2017 bid. ((CBC))

Mandel blasted Ambrose Monday for failing to represent Edmonton’s interests in cabinet.

"Our own minister, Minister Ambrose completely failed to stand up for this city and province," he said.

"I was repeatedly in Ottawa and every single MP I talked to said if your minister wants this it will happen. It didn't happen - solely sits at her feet."

Ambrose said she understands the mayor’s disappointment.

"But this bid could have come from any city in the country and the decision would have been the same."

The federal government share of hosting the fair was $700 million.

But Ambrose said the government learned from the G8 and G20 meetings and the Vancouver Olympics that security costs can quickly climb astronomically.

Mandel maintains Ottawa's share of security costs would have been more like $12 million.

"Now, the minister who is in charge of that said, ‘Well that's not going to be right because we might have to secure Fort McMurray, might have to secure Aklavik.' I don't know what their logic is, just a way in which to get out of it."

NDP MP Linda Duncan is expected to keep EXPO on the radar Tuesday when she will challenge the government during question period.