Mexican human rights activists, anti-corruption crusaders, and journalists spoke out Monday after The New York Times reported that spyware purchased by their government for use against criminals and terrorists had been turned on them.

"This is an operation of the Mexican state. The agents of the Mexican state, far from legally doing what they should do, have used our resouces to commit grave offenses," muckraking journalist Carmen Aristegui told a press conference in the capital.

"Enrique Peña Nieto needs to offer explanations," she said, referring to Mexico's president.

Aristegui and others were targeted by Pegasus software, designed to infiltrate a person's cellphone to gain access to everything on the device, The New York Times said in a story published Monday.

Pegasus, made by the Israeli company NSO Group, is capable of hijacking a smartphone's camera and microphone to turn the device into a surveillance tool, the daily said.

The Mexican government has bought roughly $80 million worth of software from NSO Group over the past six years, according to The Times, which said that the company has a policy of selling only to governments and of requiring assurances that the spyware will be used only for law enforcement and counter-terrorism.

Mexico's government denied having spied on reporters and activists.

Researchers at the University of Toronto's Citizen Lab, which analyzed the hacking attempts, said they found NSO code on the targets' smartphones.

Three years ago, Aristegui uncovered what became known as the "Casa Blanca" (White House) scandal, involving a luxury home provided to first lady Angelica Rivera on favorable terms by a contractor that did extensive business with the government.

Though public reaction forced Rivera to give up the residence, it was Aristegui who suffered most for the revelations.

The respected journalist lost her job, was sued, and received death threats. She subsequently managed to put together her own media outfit, Aristegui Noticias.

Citizen Lab determined that the Pegasus software was deployed against Aristegui, her teenage son, and two Aristegui Noticias reporters.

Another target of the spying was Juan E. Pardinas, director of the Mexican Institute for Competitiveness, which advocates for stronger laws against corruption.

Three attorneys with the Miguel Augustin Pro Juarez Human Rights Center (Centro Prodh), including the institution's head, were likewise targeted.

Centro Prodh seeks to aid victims of abuses by the security forces.

Eight attempts were made to hack the smartphone of journalist Carlos Loret de Mola while he was investigating extrajudicial executions by the Federal Police.