The anti-government demonstrations in Venezuela have led to the deaths of more than 40 people and the detention of some 850 people, including at least 77 minors, the United Nations’ human rights office said Tuesday.

Rights office spokesman Rupert Colville said 696 people were detained by security forces last Wednesday alone – the highest such tally in a single day in the South American country in at least 20 years.

Colville said in Geneva that of the people killed, 26 were shot by pro-government forces, five were killed in house raids and 11 were reportedly killed by “unidentified individuals” linked to incidents of looting. He said one member of the Bolivarian Guard was reportedly killed in the state of Monagas.

US ANNOUNCES SWEEPING SANCTIONS AGAINST VENEZUELAN PRESIDENT NICOLAS MADURO, STATE-OWNED OIL COMPANY

Venezuela has been embroiled in political power tug-of-war since opposition leader Juan Guaido declared himself interim president last week as part of a campaign to remove disputed President Nicolas Maduro.

On Monday, Guaido called for his supporters to step up protests “in every corner of the country” and around the world, mounting pressure against Maduro who faces intensifying scrutiny over last year’s controversial presidential elections.

“I am the only legitimate president of Venezuela,” Guaido told broadcaster ARD. “There was no election in 2018. Maduro’s term in office is over so he is unlawfully in office and is governing as a dictator.”

The head of state claim by the 35-year-old leader of the opposition-led national assembly has garnered the backing from most Western powers led by the United States.

On Monday, the Trump administration announced billions of dollars in new sanctions against Maduro and the country’s state-owned oil monopoly PDVSA. The economic sanctions were aimed at increasing pressure on Maduro to cede power to the opposition.

VENEZUELAN OPPOSITION LEADER CALLS FOR MORE PROTESTS AS MADURO REMAINS DEFIANT TO MOUNTING PRESSURE

Venezuela is very reliant on the U.S. for its oil revenue, sending 41 percent of its oil exports to the U.S. Maduro could however divert the roughly 500,000 barrels per day of oil currently being sold to Gulf Coast refineries to markets in Russia, China, India, Malaysia, and Thailand.

Meanwhile, National Security Adviser John Bolton warned that “all options are on the table” against Venezuela, who could face a “significant response” if any harm came to the U.S. diplomatic personnel, Guaido or members of the national assembly.

Bolton may have inadvertently revealed the Trump administration’s next move against Venezuela when photographers captured a note on a legal pad that clearly read: “5,000 troops to Columbia.”

White House officials confirmed to Fox News that the note was related to the ongoing crisis in Venezuela.

JOHN BOLTON'S WRITTEN NOTE ON 'TROOPS TO COLOMBIA' RAISES EYEBROWS

Russia and China, who are among the countries supporting Maduro’s administration and have bankrolled his government, strongly criticized the U.S. sanctions on Monday.

Russian Foreign Minister Sergei Lavrov said the sanctions completely undermined confidence in an international financial system that is dominated by the U.S.

“Russia is doing everything to support the lawful government of Maduro,” he said, according to Russian news agency Interfax.

Kremlin spokesman Dmitry Paskov called the sanctions “illegal” and added that the restrictions continue an “undisguised interference in its (Venezuela’s) internal affairs.”

Chinese Foreign Ministry spokesman Geng Shuang said historical experience showed foreign interference “only makes situations more complicated”.

“The relevant country’s sanctions on Venezuela will lead to the deterioration of conditions of people’s lives,” Geng told a regular news briefing in Beijing, referring to the United States.

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“They should bear responsibility for the serious consequences from this,” he said, according to Reuters.

The Trump administration had long held off targeting Venezuela’s oil sector for fear that it would hurt U.S. refiners and raise oil prices for Americans.

Fox News' Gregg Re and Samuel Chamberlain, as well as the Associated Press, contributed to this report.