US President Donald Trump said on Friday he focused on humanitarian aid for Venezuelans during a phone call with Russian President Vladimir Putin, backing away from his administration's recent harsh rhetoric about Russian involvement in the crisis.

In a rare call, Trump and Putin spoke for more than an hour, their first known conversation since December and since tensions flared in Venezuela, where Washington backs opposition leader Juan Guaido and Moscow supports President Nicolas Maduro.

"We talked about many things, Venezuela was one of the topics," Trump told reporters at the White House.

"And he (Putin) is not looking at all to get involved in Venezuela other than he would like to see something positive happen for Venezuela, and I feel the same way. We want to get some humanitarian aid - right now people are starving, they have no food, they have no water," he said.

Trump's comments stand in sharp contrast to those made a month ago, after Russia sent a contingent of special forces to Caracas.

"Russia has to get out," Trump told reporters at the time. On Friday, he made no mention of the troops.

Trump's call with Putin came days after an attempted uprising led by Guaido failed to turn key military figures against Maduro.

Trump's closest advisers have sharply objected to Russia's presence in the hemisphere and blamed Moscow for helping keep Maduro in place. Secretary of State Mike Pompeo said Maduro had been ready to flee Venezuela on Tuesday but reversed his plan after Russia intervened. Russia denied the allegation.

White House spokeswoman Sarah Sanders said there was no daylight between Trump on Pompeo on the issue.

"The president was relaying what President Putin said him - that's it," Sanders told reporters.

The United States and most other Western countries support Guaido, who invoked the constitution in January to declare himself interim president, arguing that Maduro's 2018 re-election was illegitimate.

Russia supports Maduro, who has said Guaido is a puppet of Washington.

Pompeo and his Russian counterpart, Sergei Lavrov, are slated to meet on Monday on the sidelines of an Arctic Council meeting in Finland - their second full-fledged encounter.

Venezuela is suffering from deep economic recession, hyperinflation and food and medicine shortages.

The United States has sent hundreds of tons of food and medical supplies for Venezuela to neighbouring Colombia and Brazil, but has not yet been allowed to deliver it.

Trump has consistently said he would not rule out military options for the crisis, though he has emphasized he hopes for a peaceful transition of power.

Pompeo and Trump's national security adviser John Bolton met with acting Defense Secretary Patrick Shanahan at the Pentagon on Friday, but there were no immediate announcements from the meeting, the White House said.

The United States has imposed sanctions on Venezuela's key oil sector to choke off revenues to Maduro and is considering further sanctions, officials have said.