Maduro cited a report published Wednesday by the news outlet "The Intercept" based on a March 2011 article in an internal US National Security Agency newsletter that it said was obtained by former NSA contractor Edward Snowden, AP reported on Friday.
Maduro said on national television late Wednesday that he was ordering an investigation and that US charge d'affaires Lee McClenny would be summoned for a formal protest. The US and Venezuela have not had ambassadors in each other’s capitals since 2010.
"I have ordered our foreign minister to begin an integral review of our relation with the US government," said Maduro.
Telesur, a regional television network, said it obtained a copy of the NSA document that purportedly shows US intelligence spied on internal communications of the state oil company PDVSA all the way up to Ramirez.
US State Department Spokesman John Kirby said Thursday that the US would respond via diplomatic channels.
"We've seen many times that the Venezuelan government tries to distract from its own actions by blaming the United States or other members of the international community for events inside their country," Kirby added.