The U.S., Canada and Mexico might reach a basic deal on the North American Free Trade Agreement, or NAFTA, in the coming weeks after Washington dropped one of its most contentious demands, according to a Mexican private sector business leader, Reuters reported.

Washington's reported withdrawal of its demand that all cars made in the three NAFTA countries have 50% American content boosted hopes that a new agreement is possible, said Moises Kalach, head of the international negotiating arm of Mexico's CCE business lobby.

"There are positive signs that there is the will, and that the window of opportunity we were looking at, is happening," Kalach, whose lobby group represents the Mexican private sector at the NAFTA talks, told Reuters.

However, Jerry Dias, head of the Canadian Unifor union with close ties to Ottawa's negotiators, said he was doubtful that an agreement in principle could be reached due to unresolved issues, including Washington's demand of a "sunset clause" that could automatically terminate NAFTA after five years and its desire to limit access to its agricultural markets.