Canadian Prime Minister Justin Trudeau said Monday it was "likely" that one of the country's nationals kidnapped by Islamic militants in the southern Philippines nearly nine months ago had been killed.

"It is with deep sadness that I have reason to believe that a Canadian citizen, Robert Hall, held hostage in the Philippines since September 21, 2015, has been killed by his captors," Trudeau said in a statement.

Members of the notorious kidnap-for-ransom Abu Sayyaf gang said they would murder Hall if they did not receive 300 million pesos ($6.5 million) ransom by Monday.