Donald Trump intends to delay signing a revised version of the North American Free Trade Agreement (Nafta) until after the midterm elections, a move aimed at reaching a better deal with Canada and Mexico.

Trump said in an interview with Fox Business broadcast on Sunday that he could quickly sign an agreement with the US neighbors “but I’m not happy with it. I want to make it more fair.”

Asked about the timing of an agreement, Trump said: “I want to wait until after the election.”

The US and Canada have been engaged in a tit-for-tat dispute over Trump’s tariffs on Canadian steel and aluminum. Canada announced billions of dollars in retaliatory tariffs against the US on Friday. The president signaled such moves could continue.

In his Fox interview, Trump again threatened to impose tariffs on imported cars, trucks and auto parts, saying: “The cars are the big ones.”

The move has been viewed as a possible negotiating ploy to restart Nafta talks, which could resume following Sunday’s elections in Mexico.

If the US moved forward with tariffs on auto imports, it would be a blow to Canada’s economy because of the critical nature that the auto industry plays in the country. The US commerce department is expected to hold hearings on auto tariffs in late July and to complete its investigation into auto imports later this summer.

Trump has sought to renegotiate Nafta to encourage manufacturers to invest more in US and shift production from low-wage Mexico. The talks have stalled over several issues, including Trump’s insistence on a clause that would end Nafta every five years unless all three countries agree to sustain it.

The president has suggested he may pursue separate trade pacts with Canada and Mexico. But any reworked deal would need to be considered by Congress, and negotiators missed a self-imposed deadline to wrap up the talks by mid-May to allow it to be considered by lawmakers before the November elections.

Trump has clashed with the Canadian prime minister, Justin Trudeau, over trade, with the US president tweeting last month after departing the G7 meetings in Quebec that Trudeau was “weak” and “dishonest”.

Trump and Trudeau spoke by phone late on Friday. Trudeau’s office said the prime minister “conveyed that Canada has had no choice but to announce reciprocal countermeasures” to the US tariffs.