Alberta separatists have delivered more than 300,000 signatures to elections officials in western Canada , in support of their attempt to force an independence referendum in Canada’s oil-rich province.

But the effort stumbled immediately as a separatist-linked group posted the personal data of nearly three million residents online in one of the largest data breaches in Canadian history, fomenting fears of a possible political interference crisis.

On Monday, hundreds of supporters gathered in Edmonton, the provincial capital, as Mitch Sylvestre, a separatist leader, delivered the petitions to Elections Alberta.

“We’re not like the rest of Canada ,” Sylvestre told reporters and attendees. “We’re 100% conservative. We’re being ruled by Liberals who don’t think like us.”

A minority of residents of the oil-rich province have long argued that the province’s woes are due to the structure of payments to Canada’s federal government and a perceived inability to get their vast fossil fuel reserves to market.…