Meanwhile, Vice President Mike Pence called on countries around the world to stop supporting President Nicolas Maduro's regime.
He singled out Russia, saying: "The United States views Russia's arrival of military planes this weekend as an unwelcome provocation and calls on Russia today to cease all support for the Maduro regime."
Russia's foreign ministry says it sent the personnel in accordance with the Venezuelan constitution and a bilateral agreement with the government there.
Their comments came during a meeting at the White House with Fabiana Rosales, the wife of Venezuelan opposition leader Juan Guaido.
President Trump and Mr Pence lavished praise on Ms Rosales who has emerged as a prominent figure in her husband's campaign.
"We are with Venezuela," said President Trump at the start of a meeting with Ms Rosales and other opposition figures.
The US was the first nation to recognise Mr Guaido as interim president, asserting that Mr Maduro's re-election last year was illegitimate.
They have since stepped up sanctions and other diplomatic measures in the hope of forcing him to give up power.
President Trump said the Venezuelan people have been through "unfathomable" trials under Mr Maduro as food and medicine have become scarce, crime has soared and, more recently, blackouts have struck most of the country.
An estimated three million people have fled Venezuela, most to neighbouring countries but thousands to the US as well.