US Commerce Secretary Wilbur Ross on Friday reiterated the threat of leaving the North American Free Trade Agreement if the outcome of the ongoing negotiations with Mexico and Ottawa does not satisfy Washington. 

"The president has made clear that if they don't work, he is going to pull out. That shouldn't be a shock to anyone," Ross said at a conference organized by the Washington Post. 

Trump ordered the renegotiation of NAFTA, which he has called the worst trade deal ever signed. He has threatened to exit the agreement if the US does not get a better deal.

"We need to fix this deal. It has not worked the way it intended to. A trade deal is supposed to benefit both sides," said Ross, noting that since its entry into force in 1994, the US trade deficit with Mexico has exploded.

Asked about the progress made so far in the two rounds of discussions, one in August in Washington and the other that had just ended in Mexico, Ross said, "It's too early to make a judgment. 10 days of discussion is not a lot."

A third round is planned for the end of September in Canada.  

Ross said the strategy "is to start with the easy things ... try to build some momentum and a sense of togetherness as you move to the harder issues." 

However, compared to what has been done before in other trade negotiations the progress in the NAFTA talks has been "extremely rapid."

But he warned that the talks "can't drag out too long because of the political calendar," with elections coming up in Mexico and Canada. 

In addition, the US Congress's "fast-track" procedure for approving new trade deals without changes expires in July, and midterm legislative elections are scheduled for November.