By Kylie Madry and David Shepardson

MEXICO CITY/WASHINGTON (Reuters) -The U.S. and Mexico still have "differences" of opinion regarding Mexico's recovery of a coveted air safety rating, Mexico's president said on Thursday.

The U.S. Federal Aviation Administration (FAA) downgraded Mexico to the Category 2 air safety rating more than two years ago, citing safety concerns. The decision means Mexican airlines cannot open new routes to the United States.

U.S. Transportation Secretary Pete Buttigieg visited Mexico on Wednesday, where Mexican officials said the rating change would be discussed, but two sources with knowledge of the matter cautioned that the rating recovery would not coincide with his trip and said there was no specific timetable for restoring the rating.

The U.S. wants to make clear any decision to restore Mexico's safety rating would be based on technical merits, not politics, the sources added.

Mexican President Andres Manuel Lopez Obrador said at a news conference on Thursday that the U.S. was "bargaining" with Mexico over the rating and that a change to cargo flights was another sticking point between the countries.

Lopez Obrador wants cargo flights to land at the new Felipe Angeles (AIFA) airport in Mexico City rather than the more centrally located Benito Juarez airport to free up space, but said some U.S. carriers are reluctant to move.

"Yesterday, we met with the transportation secretary," Lopez Obrador said. "There are differences. But these are important matters, and we must come to an agreement."

A joint statement from the U.S. and Mexican transportation agencies released by USDOT late Thursday did not address Mexico's air safety rating but said both governments are committed to the successful development of AIFA "in ways that will bolster the U.S.-Mexico air transportation relationship."

The statement added the U.S. and Mexico discussed further steps to promote the expansion of commercial operations at AIFA, "including the flexibility and support that will help U.S. carriers to successfully launch operations there."

Last week, the FAA wrapped up one of a series of audits on Mexico. Mexican Transportation Minister Jorge Nuno said the audit was Mexico's "last" in a statement Wednesday, implying a positive resolution.

Mexico has revamped compliance with international standards on licensing, aircraft operations and airworthiness of craft, among other things.

The FAA declined to respond to Lopez Obrador's comments.

(Reporting by Kylie Madry and David Shepardson in Washington. Editing by Rosalba O'Brien and Gerry Doyle)