Urzua underlined that public policy decisions were made "without sufficient support" under Obrador's left-wing regime.
"I am convinced that all economic policy should be enacted on the basis of evidence, taking care of different potential effects and that it is free from all extremism, be it from the right or left", he said. "However, these convictions did not resonate during my tenure in this administration".
"However, during my administration, the above convictions were not shared", said Urzua, who occupied the post since December 1, when the current administration began.
By naming Urzua's protege, Herrera, to the top job within an hour of the former's resignation, Lopez Obrador stemmed a sell-off in Mexican assets that saw the peso fall as much as 2 percent and the stock market drop 1.4 percent. It fell 0.4% to 19.2344 per dollar at 9:01 a.m.in NY.
Urzua has been a long-standing ally of Lopez Obrador, being his finance secretary when AMLO, as the president is widely known, was mayor of Mexico City last decade.
Despite his comments on fiscal discipline, Herrera made clear he was also on board with Lopez Obrador's expansive infrastructure plans, and vowed to stay in the post until asked to leave.
Urzua deeply cut back spending programs in a strategy aimed at cleaning out corruption and largesse with a new, more centralized model of assistance.
In a video message to announce his successor, Lopez Obrador said Urzua was not comfortable with the decisions being taken to upend what the president frequently calls the neoliberal era in Mexico, starting in the 1980s. Articles appear on euronews.com for a limited time.