Secretary of State Antony Blinken and other top US officials visited Mexico on Monday for high-level economic talks, with President Andres Manuel Lopez Obrador striking a conciliatory tone despite trade tensions.

Washington in July filed a formal complaint against Mexico under a North American free trade agreement, saying its energy policies discriminated against US firms.

Lopez Obrador says the complaint is unjustified, but his government has pledged to work toward a solution.

Asked if he would discuss the energy dispute with Blinken, Lopez Obrador told reporters that there was no fixed agenda for their meeting, but that if the issue was raised, it would "be dealt with."

He welcomed the tone of a recent letter from US President Joe Biden, saying Mexico appreciated its "respectful attitude" compared to the trade complaint, which he described as "not the most diplomatic."

Lopez Obrador's push to roll back the effects of liberalization that he says benefited private companies has alarmed foreign investors and environmentalists, who see the moves as favoring fossil fuels over renewable energy.

Washington has requested consultations about the energy dispute under the US-Mexico-Canada Agreement, the first step in a process that could lead to retaliation over actions it says harm US firms and impedes development of clean energy.

Lopez Obrador visited Washington in July for talks with Biden, who said that the two sides needed to rebuild relations.

A month earlier, the Mexican leader snubbed Biden by refusing to participate in the Summit of the Americas in Los Angeles on the grounds that Cuba, Venezuela and Nicaragua had not been invited.

During a meeting with Mexico's Foreign Minister Marcelo Ebrard, Blinken voiced appreciation for collaboration on issues including "the shared threat of fentanyl production and trafficking, addressing migration in a safe, orderly, and humane manner... and advancing our shared economic interests," the State Department said.

The top US diplomat, accompanied by US Secretary of Commerce Gina Raimondo and Deputy US Trade Representative Jayme White, was later due to co-chair the US-Mexico High-Level Economic Dialogue.

Before the Covid-19 pandemic, Mexico was the second-largest trading partner of the United States, behind China, with more than $675 billion in annual trade, according to US figures.