NDP Leader Tom Mulcair says apparent efforts to spy on Brazil give Canada a black eye.

Speaking at a news conference, Mulcair calls the reported attempt by Canada's electronic eavesdropping agency to monitor Brazil's Ministry of Mines and Energy "a huge mistake."

A Brazilian television report said the metadata – or indexing details – of phone calls and emails from and to the ministry were targeted by the Ottawa-based Communications Security Establishment Canada to map the ministry's communications.

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Mulcair says it's further proof that the Conservatives have no ethical boundaries.

Prime Minister Stephen Harper says he's very concerned" about the reports of spying.

The CSEC monitors foreign computer, satellite, radio and telephone traffic for intelligence of interest to Canada.