MEXICO CITY, June 1 (Xinhua) -- Mexico will focus on persuading the United States to eliminate existing tariffs during the review process of North America's trilateral free trade agreement, Mexican Economy Secretary Marcelo Ebrard said Monday.

The economy secretary said at an event that the U.S. delegation put forward several proposals following the first round of formal negotiations last week on the review of the United States-Mexico-Canada Agreement (USMCA).

"There are a wide range of proposals from the United States regarding content, rules of origin, provisions concerning third countries, and so on," Ebrard told reporters, mentioning issues such as steel, aluminum, the automotive industry and economic security.

U.S. President Donald Trump's administration is carrying out a "tremendous" transformation to the global trading system, including the USMCA, he said.

Under Trump, the United States is implementing differentiated tariffs on imports that vary depending on where goods are produced, a policy that Mexican officials say differs drastically from the international trading system that has prevailed in recent decades, especially with regional trade partners Mexico and Canada.

"What the United States is creating now is a system in which different parties will be charged different tariffs. It's very complicated to understand," the economy secretary said.

While Mexico's position is to secure the lowest possible tariffs, the ideal scenario would be a return to free trade, he said.

The economy ministry plans to present a series of proposals at the next meeting that reflect the legitimate interests of the industrial sector, he added.

Mexican and U.S. officials confirmed last week that the second round of bilateral talks on the USMCA review will be held on June 16-17 in Washington, D.C., and will cover agricultural issues and conditions for fair competition, in addition to continuing discussions on rules of origin.

The third round will take place during the week of July 20 in Mexico City and will focus on finalizing outstanding issues in preparation for a joint review by all three USMCA partner countries later this year, as stipulated under the agreement.