Mexican business leaders expressed confidence Thursday that an agreement on the modernization of the North American Free Trade Agreement (NAFTA) will be reached within the next few days.

Gustavo de Hoyos, president of the Mexican Employers' Association, told reporters that significant progress has been made in recent talks between negotiators for Mexico and the United States.

"This is the closest we've been (to reaching a deal) since the start of negotiations," de Hoyos said.

"There have been significant advances and we are hoping it will be finalized sometime between now and next Wednesday," he said.

His remarks came a few hours before he boarded a plane to Washington D.C., to join the team renegotiating NAFTA.

Francisco Cervantes, president of the Confederation of Industrial Chambers of Mexico, said he would also be heading to Washington D.C. amid prevailing optimism that an agreement would be reached.

"In the end, it comes down to willingness, and right now that willingness is flowing in a positive way," Cervantes told reporters. "Who knows? Maybe I'll get the news mid-flight."

Both de Hoyos and Cervantes are part of the so-called "side room," a group of private-sector representatives that advises the government on industrial and business issues.

The two main sticking points, Cervantes said, are a sunset clause that calls for the deal to be renewed every five years, and the seasonality of agricultural products, both of which U.S. President Donald Trump has insisted on.

The two sides resumed negotiations a few days ago with the notable absence of Canada, the third partner in NAFTA.