MEXICO CITY — The impact of a first major anti-corruption drive by Mexican President Andrés Manuel López Obrador spread deep into the political class on Wednesday as the probe threatened to involve top officials in the last government, including the president.

At the center of the investigation is Emilio Lozoya, a former chief executive of state oil company Petróleos Mexicanos (Pemex), who the government has accused of financial irregularities during his time at the helm between 2012 and 2016.

Mexico's attorney general said a warrant for Lozoya's arrest has been issued after allegations surfaced about his role in the purchase by Pemex of struggling fertilizer businesses, as well as his dealings with scandal-plagued Brazilian construction firm Odebrecht.

Lozoya has yet to speak publicly on the accusations, but his lawyer said on Wednesday that top officials from the previous administration, including former President Enrique Peña Nieto, should testify on what they knew about Pemex's operations.

Noting that the ministries of finance, economy and energy all sit on the company's board, Lozoya's attorney Javier Coello said the government had to sign off on whatever Pemex did.

"I would even summon President Peña Nieto," Coello told broadcaster Televisa. "Nothing in this country moved unless there were instructions from the president."

Mexican Attorney General Alejandro Gertz has not detailed the case against Lozoya but said it had been in preparation for months. He too said the role played under Peña Nieto by the ministries on Pemex's board needed to be examined.

The biggest result of the probe so far was the arrest on Tuesday in Mallorca, Spain, of steel magnate Alonso Ancira, who the government accuses of paying Lozoya bribes.

Arrest warrants for other suspects have also been issued and Coello said Lozoya's Mexico City home had been raided.

López Obrador, a veteran leftist, took office in December pledging to crack down on public sector corruption in Mexico, which he says is a legacy of his political adversaries.

He told his regular morning news conference the probe was not a "political persecution" and that the charges stemmed from investigations already underway under his predecessor.

Lozoya helped run Peña Nieto's 2012 election campaign and was a major figure in the last administration until his abrupt departure from the struggling Pemex in February 2016.

The 44-year-old has always denied wrongdoing and defended the fertilizer business acquisitions as a wise investment.

In 2017, he had to deny having funneled cash to Peña Nieto's election campaign after Brazilian newspaper O Globo alleged that Lozoya had taken $10 million in bribes in 2012 from a former executive of Odebrecht.

By then, some senior officials in the then-ruling Institutional Revolutionary Party (PRI) were privately forecasting he would eventually face prosecution.

The finance ministry's anti-money laundering czar has said the allegations center on bribes paid in connection with the $475 million purchase by Pemex of a fertilizer plant from Ancira's company Altos Hornos de Mexico.

The official, Santiago Nieto, said the case had links to Odebrecht, whose executives have testified about bribes to politicians across Latin America.

Last week the government banned Lozoya from public service for 10 years as part of a probe into the 2014 purchase of a fertilizer plant, which was out of service.

The decision to go after him comes just days ahead of state elections on Sunday that will provide the first major test of Lopez Obrador's popularity since he took office.

Speculation has swirled for months about whether López Obrador would go after high profile targets to underline his commitment to end corruption, a chronic malaise blamed for hurting growth and stoking violence and inequality in Mexico.

Jesús Ortega, a former campaign manager for López Obrador and senior figure in the center-left opposition Party of Democratic Revolution, said the Pemex move appeared motivated by the president's need to satisfy his base.

"The pressure within his own party and the pressure within his cabinet had become enormous," Ortega said.

Former President Peña Nieto signaled his own intent to clean up politics by having former teachers union boss Elba Esther Gordillo arrested in the third month of his government.

Gordillo later ended up under house arrest and was released shortly after López Obrador won office in July.

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