(CNN)Mexico's finance minister, Carlos Urzúa, quit abruptly on Tuesday, with a letter of resignation that appeared highly critical of the current administration, and raised questions about the president's much-vaunted promise to reduce corruption.
Mexican finance minister quits with scathing resignation letter
He tweeted a copy of the letter -- addressed to Mexican president Andrés Manuel López Obrador -- which suggested that the current administration's policymaking was not "based on evidence" or "free of extremism."
"There were a lot of discrepancies in economic matters," the letter read.
"Some of those because this administration has made public policy decisions without enough support. I am convinced that all economic policy must be carried out based on evidence, taking care of the diverse effects these decisions can have and they must be free of all extremism. However, during my time I did not find this was the case."
Urzúa also suggested that some appointments within the administration had been made for the wrong reasons. "I find it unacceptable the imposition of officials who have no Public Treasury knowledge. This was motivated by influential figures of the current government with a patent conflict of interest," he wrote.
López Obrador, known commonly as AMLO, responded on his Facebook page, saying that he had accepted Urzúa's resignation and that he had named undersecretary Arturo Herrera Gutiérrez to fill the role.
The president is a left-leaning, anti-establishment politician who won his office just last year in a long-shot campaign. In his first year in office, he has led the country to renegotiate a free trade agreement with the US and Canada, and to placate the United States over migration by stepping up controls at Mexico's southern border.
During his acceptance speech, AMLO promised to eradicate corruption from the country. "Corruption is not a cultural phenomenon but it is the result of a political regime in decay. We are absolutely certain that this evil is the principal cause of social inequality and of economic inequality," he said back then. "Because of corruption, violence has erupted in our country."
As part of his fight against corruption, AMLO vowed to sell the luxurious presidential plane and scrapped plans for an already partially-built new airport in Mexico City.
But Urzúa is not the first to express doubt about the new president's approach to policy; critics have warned that he might have an authoritarian streak, and compared him to Venezuela's former far-left leader Hugo Chavez.