At least 40 people are believed to have been killed in Venezuela's recent violence, including 26 shot by pro-government forces, five killed in house raids and 11 during looting, U.N. human rights spokesman Rupert Colville said on Tuesday.

He said more than 850 people were detained between Jan. 21 and Jan. 26, including 77 children, some as young as 12. On Jan. 23, 696 people were detained across the country, the highest daily number of detentions in Venezuela in 20 years.

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The Trump administration on Monday sanctioned Venezuela’s state-owned oil company, ratcheting up pressure on socialist President Nicolas Maduro to cede power to the U.S.-backed opposition in the oil-rich nation in South America.

The action means Maduro’s embattled government would lose access to one of its most important sources of income and foreign currency along with around $7 billion in assets of the state-owned company, Petroleos De Venezuela S.A.

Hours after the White House announced the sanctions, Maduro went on state TV and called the U.S. action “immoral, criminal.” In words directed at President Donald Trump, he said, “Hands off Venezuela!”

The sanctions follow the unusual decision by more than 20 countries, including the U.S., to recognize the opposition leader of the National Assembly, Juan Guaido, as the interim president of Venezuela. Maduro was re-elected last year in an election widely seen as fraudulent. The once prosperous nation has been in an economic collapse, with several million citizens fleeing to neighboring countries.

“We have continued to expose the corruption of Maduro and his cronies, and today’s action ensures they can no longer loot the assets of the Venezuelan people,” national security adviser John Bolton said at a White House news conference to announce the sanctions with Treasury Secretary Steven Mnuchin.