Canadian Prime Minister Mark Carney said President Donald Trump’s threats to make Canada the 51st state prompted him to prepare for a possible American invasion, though he acknowledged it was an unlikely outcome.

In a wide-ranging interview with the New York Times, Carney offered a closer look at how he has navigated strained relations between Canada and the U.S. The prime minister was pressed on how he took Trump’s remarks about Canada becoming the 51st state in the union.