Clashes erupted across the country in April 1 during protests in anger at Maduro's handling of an economic and political crisis.
The aides spoke on condition of anonymity after being briefed on the action, which they say could come as early as later in the day.
The Trump administration imposed sanctions on the chief judge and seven other members of Venezuela's Supreme Court on Thursday as punishment for seizing powers from the opposition-led Congress earlier this year, U.S. officials said. Protests against the Maduro government have escalated and there have been calls for Maduro to step down.
On Thursday, U.S. President Donald Trump called the situation in Venezuela a "disgrace to humanity", and said the deadly political crisis is possibly the worst of its kind in "decades". But sanctions so far have stopped short of hitting the oil sector in Venezuela, which is a major USA oil supplier.
The new sanctions package was aimed at stepping up pressure on supporters of the leftist government of Venezuelan President Nicolas Maduro amid growing United States concern over a crackdown on mass street protests.
Meanwhile, the U.S. warned at the United Nations that Venezuela's crisis was worsening and could escalate into a civil conflict.
The Supreme Court justices added to the sanctions blacklist were Supreme Court President Maikel Moreno, Calixto Ortega, Arcadio Delgado, Federico Fuenmayor, Carmen Zuleta, Lourdes Suarez Anderson and Juan Jose Mendoza.
UN ambassadors from Bolivia and Uruguay joined Caracas in rebuffing U.S. attempts to address the ongoing in Venezuela before the UN Security Council. Maduro, the successor to late leader Hugo Chavez, says his foes are seeking a violent coup.
Venezuelan opposition leader Henrique Capriles said he was barred from leaving the country Thursday as he planned to address a United Nations session in NY about the country's escalating violence.
"It is beyond appalling that President Maduro would invoke the Holocaust in an effort to protect himself and his regime, and to attack and defame the opposition", said Dina Siegel Vann, AJC Director of Latino and Latin American Affairs. "And we are going to defeat them, these 21st century Nazis".
"I will not be able to attend the meeting with the [UN] High Commissioner for Human Rights".
Contre les restrictions de la justice, Khalifa Sall boude les visites
La note en cours de délibéré a été transmise à la chambre d'accusation au lendemain de l'audience, le 12 mai. Assises toutes à terre, elles ont scandé: "libérez khalifa Sall ".
Capriles, a sports-loving lawyer who has tried to shake the opposition's reputation of elitism by focusing on grassroots efforts with poor Venezuelans, narrowly lost the 2013 vote against Maduro, and the two frequently lock horns.
Diapers have become prized products in Venezuela due to widespread shortages of basic domestic items.
The State Prosecutor's Office said three National Guard sergeants would be charged later on Thursday for their "presumed responsibility" in Castellanos' killing.
Earlier in the week, a 15-year-old was shot dead when out buying flour for his family's dinner.
Most shops and businesses in San Cristobal were closed and guarded by soldiers after widespread looting amid a deepening economic crisis.
Police have fired tear gas and protesters have hurled rocks and Molotov cocktails in near-daily clashes. That sparked now-familiar scenes of masked youths brandishing shields and throwing stones at the security line.
Analysts are growing increasingly concerned about the possibility of huge disruption in Venezuelan oil exports.
Uruguay's United Nations ambassador Elbio Rosselli, president of the Security Council for May, said that at this point Uruguay believed the Venezuelan crisis should be handled within the region.
"It is a very, very frightful problem".
"It has been unbelievably poorly run for a long period of time, and hopefully that will change and they could use those assets for the good and to take care of their people", he said.
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