Mr. Maduro has led Venezuela’s economy into shambles and prompted an exodus of millions of people into neighboring South American states. The sanctions are among the biggest hits to Venezuela’s economy since the United States banned Venezuela’s state oil company last January, said Francisco Monaldi, a Venezuela energy expert at Rice University in Houston.

“Rosneft will now have to think how much Venezuela is worth from a business standpoint, compared to the costs of remaining under sanctions,” Mr. Monaldi said.

But, he added, the sanctions could misfire if Rosneft concludes that the higher costs of doing business in Venezuela are justified by the geopolitical benefit of helping out Russia’s key ally in South America.

Rosneft sells about two-thirds of Venezuela’s oil, largely to Asia, and often by obscuring the cargo’s source and destination. Officials said Mr. Maduro was taking the profits from the oil sales facilitated by Rosneft to hang onto power, in part by bolstering the Venezuelan military and its harsh crackdown against the public.

Rosneft’s trading subsidiary was created in 2011 to help its Moscow-based parent company carry out foreign projects, including shipping crude oil. In the last few years, faced with American and European sanctions, Rosneft has pushed deeply into places like Cuba, China, Egypt and Vietnam.

Its two largest customers are China and India, both of which have struggled to procure sufficient oil supplies after the Trump administration imposed sanctions against Iran. In the case of India, where Mr. Trump is scheduled to visit next week, the government in Delhi has been forced to find new suppliers — including from the United States.

Additionally, the world is currently flooded with oil since the coronavirus is cutting millions of barrels a day of demand in the Chinese market. Curtailing Venezuela’s 700,000 barrels of daily production should have little if any impact on global oil prices.