(Bloomberg) -- Venezuela’s Tareck el Aissami resigned as the nation’s oil minister as an investigation escalated into corruption claims inside state-oil company Petroleos de Venezuela SA.

“I have decided to present my resignation as oil minister with the purpose of accompanying and backing this process,” Aissami tweeted Monday. President Nicolas Maduro accepted the resignation in a televised event that evening. It’s unclear if Aissami, a close ally of Maduro, remains as the nation’s vice president for the economy. 

Maduro launched a sweeping anti-corruption operation in recent days that’s led to the ouster of the head of the crypto oversight agency, judges and elected officials. On Sunday, Venezuela’s public prosecutor said it had begun the investigation following the anti-corruption police’s claims that a “series of individuals” had been involved in “grave administrative corruption and embezzlement.”

Six people have been arrested so far in connection with the government’s corruption probe, Public Prosecutor Tarek William Saab said in a radio interview Monday afternoon. More arrests could take place as the investigation advances, he said. 

“In this first stage, important businessmen, very important managers, senior officials of state institutions, lawmaker have been captured,” Maduro said, noting that he’s led the probe that began October. “We’re going after them all.”

According to Maduro, the government had already started implementing “draconian restructuring measures at the highest level” of the state oil company. “We are going to fully cleanse PDVSA of all these mechanisms, barbarities, of all these people who steal money there.”

Aissami hasn’t been identified as a subject of the investigation and hasn’t been publicly accused in Venezuela of any wrongdoing. It’s possible that anti-corruption investigators are examining the problems PDVSA experienced last year in collecting payments from oil sales, including accepting cryptocurrencies and working with unknown traders, said Francisco Monaldi, lecturer in energy economics at Rice University’s Baker Institute for Public Policy.

“This led to PDVSA not receiving a huge part of what it sold,” Monaldi said. “Regardless of the political reasons for which Tareck resigns, there are undoubtedly a series of events that have led to this being investigated.”

Aissami didn’t immediately respond to a request for comment through a representative. A press representative for the Maduro administration declined to comment. PDVSA and the Oil Ministry didn’t immediately reply to requests for comment.

Aissami’s tenure as oil minister didn’t make much of a mark. Just a year ago, Maduro had set the country’s oil production target at 2 million barrels a day for the end of 2022, “rain or shine.” Like the minister before him, Aissami largely failed to hit that target, with PDVSA’s current production reaching approximately 700,000 barrels a day.

He was named oil minister in April 2020, amid the crash of crude prices and US sanctions that aggravated gasoline shortages across the country. As vice president for the economy since 2017, he held wide-reaching powers, included the ability to determine ministries’ budgets and the takeover of private businesses. 

“We don’t cover up anybody’s criminal offenses,” Diosdado Cabello, the ruling socialist party’s first vice president, said regarding the corruption probe in a televised press conference Monday. “In the revolution, there’s no space for corrupt people.”

Aissami is among government officials charged by the US for international narcotics trafficking, with Donald Trump’s administration even offering a $10 million reward for information leading to his arrest. Aissami has referred to the allegations as unacceptable blackmail and lies.

“This investigation happens in the midst of a drop in the price of crude oil, the loss of markets for Venezuela and the slowdown of the economy,” Monaldi said. “Amid a scarcity of resources, it is urgent for the government to seek accountability from its officials.”

--With assistance from Nicolle Yapur and Andreina Itriago Acosta.

(Updates with comment from Maduro in second paragraph)

©2023 Bloomberg L.P.