Lopez Obrador asked the opposition to calm down and have some tea, during a regular news conference on Tuesday, describing the criticism as politically motivated.
"It's politics, don't give importance to that, it's not news," Lopez Obrador said when asked about whether General Luis Sandoval, who heads the defense ministry, enjoys privileges.
The National Defense Commission of the Chamber of Deputies summoned General Sandoval to Congress a couple of weeks ago, but he never appeared.
Lawmakers summoned Sandoval to explain what measures the armed forces were taking after a massive hack leaked classified information in September.
The leak brought to light details of Lopez Obrador's health, sensitive data on military operations, military monitoring of journalists and activists, and the armed forces' knowledge of acts of corruption between authorities and criminal groups.
Although secretaries of state are not obliged to accept legislators' invitations, these appearances - sometimes occurring behind closed doors - are seen as a tool for accountability.
Since taking office in 2018, Lopez Obrador has strengthened the armed forces' role in public security functions, such as infrastructure projects and customs activities.
Mexico's Congress last week approved extending the role of the armed forces in public security tasks until 2028.
(Reporting by Raul Cortes Fernandez and Ana Isabel Martinez; Editing by Andrea Ricci)
