Guaido, 35, says Maduro is "illegitimate" and launched a direct challenge to the former bus driver's authority last week when he declared himself acting president.
Mr Saab is a key Maduro ally and the high court is stacked with Maduro loyalists.
The US sanctions against Venezuela, which have intensified under President Donald Trump, prohibit US-based companies or people from buying and selling new debt issued by the state-run oil body, Petroleos de Venezuela (PDVSA) or the government.
On Monday, Washington announced export sanctions against Venezuela's oil firm PDVSA to choke off oil revenue and oust the incumbent president Nicolas Maduro. "It is not New Zealand's practice to make statements of recognition of governments", Peters said.
Venezuela's Supreme Court has imposed a travel ban on Guaido and frozen his bank accounts in apparent retaliation for oil sanctions imposed by the United States that are expected to severely hit an already collapsing economy.
Guaido shrugged off Maduro's efforts to choke his progress as "nothing new".
"The problem for us here - I don't know if you are aware that since October 2018 Petrotrin has stopped refining finished products for the region".
The pro-government Supreme Court has barred Guaido, who is calling for large anti-Maduro street protests this week, from leaving the country.
"You shouldn't sacrifice yourselves for the usurper and his gang", he added.
Chinese Foreign Ministry spokesman Geng Shuang said in response to the move that China maintains "Venezuelan affairs must and can only be chosen and decided by the Venezuelan people themselves".
In response to news earlier of the attorney general's plan, USA national security adviser John Bolton warned of "serious consequences for those who attempt to subvert democracy and harm Guaido", in a tweet that described Saab as the "illegitimate former Venezuelan Attorney General".
Venezuela's President Nicolas Maduro holds a copy of the Venezuelan constitution while he speaks during a meeting with members of the Venezuelan diplomatic corp after their arrival from the United States, at the Miraflores Palace in Caracas, Venezuela January 28, 2019.
Wills Rangel, a PDVSA board member, on Wednesday told Reuters the state-owned company, which is now producing 1.2 million bpd of crude, does not plan to cancel supply contracts with us clients.
Guaido is now petitioning the Bank of England to prevent Mr Maduro getting his hands on $1.3 billion (£1 billion) in gold held in London vaults. Guaidó is regarded as Venezuela's real leader by the USA and the European Union, while Russian Federation and China have thrown their support behind Maduro.
"Donald Trump has without doubt given an order to kill me and has told the government of Colombia and the Colombian mafia to kill me", Maduro said, reprising a constant accusation of his and Chavez's over the years.
In a tweet, he urged the opposition to "ignore the imperialist calls" and offered to open talks with Guaido. He has previously accused the USA of trying to orchestrate a coup. Many opposition leaders have been imprisoned in the South American nation. Over the years, Russian Federation has launched dozens of new oil wells.
Several U.S. refiners, including Chevron Corp, Phillips 66 and Valero Energy said they were studying the sanctions and would comply with U.S. laws. As recently as 2012, it exported 2.57 million bpd. of oil and fuel.
At the White House earlier this week, National Security Advisor John Bolton explained the situation.
Acting Defense Secretary Patrick Shanahan did not rule out a U.S. military deployment to Colombia.
The Trump administration has issued licenses to USA refineries that continue to operate in Venezuela; if Caracas wants to continue to sell the USA oil - "which we'd like to buy" - the money would go into blocked accounts that would be protected for the Venezuelan people, according to Mnuchin.
In the RIA interview, Maduro reiterated he was ready for talks with the opposition, but rejected calls for a snap election as blackmail.
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