The Canadian government has blocked mining giant BHP Billiton's hostile takeover bid for the fertiliser group Potash Corporation.
The government said it was not convinced that the deal was in the Canadian interest.
BHP said it was "disappointed" with the decision, but believed that the deal would benefit Canada.
BHP now has 30 days to convince Canada the deal should be approved before the government makes its final ruling.
"In Canada, our natural resources are an important economic driver," said Canada's Industry Minister Tony Clement.
"I have come to the conclusion that BHP Billiton does not present a likely net benefit to Canada."
In response, BHP said that it would continue to cooperate with Mr Clement and would "review its options".
BHP made a $38.6bn (£23.7bn) bid for the Saskatchewan-based company in August.
Last month, the province's premier asked the Canadian government to block the bid.
Potash Corporation itself had already asked a US District Court in Chicago to block it, on the basis of BHP's "false statements and half-truths".
BHP said the lawsuit was "entirely without merit".
By law, government officials in Ottawa must review takeovers by foreign companies to make sure that Canada could gain a net benefit from any deal.
Anglo-Australian BHP Billiton is the world's largest mining company, while Potash Corporation controls more than 25% of the world's supply of potash - a common name given to salts mined for fertiliser.