Canada’s prime minister sought to cool expectations about reaching a trade agreement with the US in the next 10 days, saying the talks are difficult because the Trump administration keeps changing its goals.

Canada will use all the time that is available to strike a trade deal with the United States, Prime Minister Mark Carney told reporters on Tuesday, saying the talks were complex.

The prospect of Canada reaching a trade deal with the United States by the Aug. 1 deadline appears uncertain, with Prime Minister Mark Carney insisting his government will only sign new agreement if there is one worth signing.