WASHINGTON - The United States will take action in response to growing Russian support for Venezuelan President Nicolas Maduro, a senior US official warned Monday.

US President Donald Trump's administration has sanctioned Maduro's regime and called it a dictatorship after he was re-elected in 2018 in elections widely seen as fraudulent.

"We are looking at additional sanctions, personal sanctions, economic sanctions that we think will bring more pressure," Elliot Abrams, the State Department's Venezuela envoy, told reporters.

Abrams, who did not specify what the sanctions would be, said the US had been looking closely at Russia's role in Venezuela and would not allow the level of support to go unchecked.

Abrams said Russia was mainly interested in "the oil economy" in Venezuela, while Maduro has grown increasingly reliant on Moscow over the past year.

"Russian companies are now handling more than two-thirds, more than 70 percent of Venezuelan oil," Abrams said. "So the Russian role is increasingly important."

Abrams did not speculate on whether Russia was involved in pushing Maduro to take control of the opposition-majority National Assembly on Sunday, which Washington currently considers the only democratic body in Venezuela.

Police had prevented opposition leader and self-proclaimed interim president Juan Guaido from entering the parliament, and in his absence Luis Parra, a corruption-tainted opposition lawmaker, declared himself parliament speaker.

Maduro holds actual power but Guaido's claim to the presidency is recognized by more than 50 countries, including the United States and many European nations.

Among Maduro's remaining supporters are Russia, North Korea and Cuba.

Abrams admitted that the US had underestimated the support Maduro received from Russia and Cuba, saying that the two countries had supplied Venezuela with thousands of intelligence agents.

Cuban and Russian assistance "has proved, I think, to be the two most important pillars of support for the regime, and without which it wouldn't be there," he said.

Maduro "is left with Cuba, Russia, China and a few odd dictatorships around the world, but he is losing support not only on the right, not only in the center, but on the left in Latin America," Abrams added. -AFP