A hard-hitting journalist with a daily radio program that exposed government corruption in Mexico has been fired, making her the center of a scandal that critics say points to a silencing of opposition voices in the country's media establishment.

News anchor Carmen Aristegui — called the second most powerful woman in Mexico by Forbes last year — was let go on Sunday by her program's parent media company. Her firing came after the outlet, Noticias MVS, dismissed two leading reporters on her investigative news team on March 12.

MVS said the reporters were fired because they used the company's name as a partner of a barely launching whistleblower site called Mexicoleaks, without authorization from superiors.

But prominent critics and more than 180,000 people who signed an online petition in support of Aristegui characterized the firings as retaliation against the journalists who exposed alleged conflicts of interest at the very top of Mexico's government.

In November, Aristegui and her team published a bombshell report exposing questionable terms linking the purchase of a family mansion for Mexico's president and a multi-billion-dollar concession to a Chinese consortium for a proposed bullet train in Mexico.

President Enrique Peña Nieto and First Lady Angelica Rivera said the purchase of the so-called "Casa Blanca," or White House, in the ritzy Lomas district of Mexico City was not unlawful.

But facing public outcry, Rivera later said she would be selling the house to avoid the impression of corruption over the bullet-train deal — which the government also canceled.

'Firing Carmen Aristegui to protect the brand means they don't understand the client.'

When Aristegui demanded that the two reporters, Daniel Lizárraga and Irving Huerta, be reinstated over the weekend, MVS instead moved to terminate her.

Aristegui's top-rated, four-hour-long morning radio program Primera Emisión was already being hosted by another anchor on Monday morning.

Standing amid a throng of hundreds of supporters and listeners outside the MVS studios in Mexico City, Aristegui said she would be fighting her dismissal, calling it an "unjustified" attack on freedom of expression.

She claimed her firing was planned far in advance. Mexico, Aristegui said Monday, is "a country facing an authoritarian gale."

Carmen Aristegui speaks to supporters outside the MVS studios on Monday.

The use of a phrase like "authoritarian gale" does not land lightly in Mexico.

For more than 70 years, the Institutional Revolutionary Party, or PRI, ruled the country without interruption using a mixture of repression, patronage, and strict media control — an era that followed the Mexican Revolution and is commonly called an authoritarian period in the country's history.

President Peña Nieto's election in 2012 marked a return to power for the PRI after two presidential terms under center-right governments that started in 2000.

Peña Nieto promised the PRI would govern Mexico with a new, more democratic face under his term. But critics point to a litany of recent scandals and government failures — including the Aristegui dismissal and the disappearance of 43 college students in Guerrero — to suggest the "bad old days" of the PRI's hegemonic rule are creeping back.

"It's exactly the same old Mexico, the one I left in the 1980s," said Jorge Ramos, lead anchor of US Spanish-language media giant Univision, in an interview on NPR on Tuesday. "I can't believe that there's still censorship in Mexico."

Daniel Lizárraga, one of the reporters dismissed along with Carmen Aristegui, in a screen-shot from a YouTube video introducing Mexicoleaks.

Reached by VICE News, press representatives at the president's office and at the interior ministry declined to comment directly on the Aristegui firing. But President Peña Nieto did make statements alluding to freedom of expression.

Addressing a group of students at a Mexico City college on Friday, Peña Nieto said Mexico is now "much more pluralistic than it was even twenty years ago" — a veiled allusion to the end of the 20th Century PRI era.

The interior ministry followed on Tuesday with a brief statement, calling the spat a "disagreement" between Aristegui and her employer.

"It is desirable for this conflict between individuals to be resolved, so the communications company and the reporter can continue to offer content that is valuable for Mexican society," the statement said. "The federal government has respected and permanently valued the professional and critical work of journalists, and will continue to do so."

Aristegui is known for challenging superiors, and has actually been fired by MVS before.

In 2011, MVS terminated Aristegui's contract for what it called an ethics violation, when the journalist said then-President Felipe Calderon should address allegations raised by opposition lawmakers that he had a drinking problem.

She came back to the air within two weeks.

The Mexicoleaks introduction.

There was strong push-back on social media and among leading liberal intellectuals over the latest Aristegui firing, and even among figures who have clashed with the news anchor before.

"Carmen Aristegui is an indispensable voice in our public life," leading conservative historian Enrique Krauze said in a tweet. "Her departure from MVS seriously injures freedom of expression in Mexico."

"Firing Carmen Aristegui to protect the brand means they don't understand the client … unless the client lives in Los Pinos," Mexican journalist Enrique Acevedo tweeted, referring to Mexico's official presidential residence.

Even the ombudsman for MVS made comments in the journalists' favor.

MVS ombudsman Gabriel Sosa Plata told VICE News in an interview that the unauthorized Mexicoleaks affiliation was "just the excuse" for MVS leaders to break ties with Aristegui and her staff.

"I think there is some kind of political or economic pressure for MVS to end the work relationship like this," Sosa said. "It is either a strong personal whim, or it is equally strong political pressure."

Huerta, one of the investigative journalists fired, told VICE News shortly after their "White House" investigation was published that relations were already frayed with the reporters' superiors. The report was initially posted on the anchor's separate news site, Aristegui Noticias, before MVS carried versions of it on their platforms.

"There were disagreements between the heads of MVS and Carmen's team about whether or not to publish" the report about the presidential mansion, Huerta told VICE News.

As a result of the feud between MVS and Aristegui, the media group has already released a new internal code of conduct for their correspondents and journalists, many of whom were protesting outside MVS on Monday.

'Her absence from the airwaves is a loss for press freedom.'

Press advocates expressed alarm at the Aristegui firing.

Sara Rafsky, Americas research associate for the Committee to Protect Journalists in New York, said the killings of journalists and attacks on newsrooms in Mexico show press freedoms are in a "dire" state in the country.

"In this context, someone like Carmen Aristegui, who has done fearless in-depth reporting touching the most powerful figures, and with an audience and impact on public opinion that is almost unprecedented in Mexico, [is] a vital voice," Rafsky said in an interview with VICE News.

"Her absence from the airwaves is a loss for press freedom, a loss for transparency, and a loss for democracy in Mexico," Rafsky said.