The move comes three months after Moscow drew US ire by deploying around 100 military experts in Venezuela after Washington indicated it could use force to oust beleaguered President Nicolas Maduro, a Russian ally.

"The Il-62 plane which is carrying Russian technicians who have been in Venezuela over the past months... is leaving Caracas for Moscow on June 26," the Russian embassy in Caracas said in a post on Facebook.

An embassy press attache told AFP "one plane" was departing for Moscow, declining to explain the timing of the move or provide any other comments.

In the statement, the embassy sought to play down the nature of cooperation as "fairly routine maintenance work", saying it would continue.

"Russia delivered to Venezuela high-level equipment that requires regular maintenance. Furthermore, Russian specialists provided technical training to Venezuelan staff"," the embassy said.

"Unlike reported, it was not a Russian military presence but the fulfilment of maintenance contracts, without any purpose of destabilisation."

Russian experts are leaving Venezuela as Russia's Putin is gearing up for talks with Trump on the sidelines of the G20 summit in Japan on Friday.

In March, Moscow sent around 100 experts and equipment to Caracas, where Russian mercenaries are also believed to be operating.

Moscow said at the time that they will remain in the country "for as long as needed."

The highly publicised move was seen as a show of support for Maduro, who has been locked in a months-long power struggle with opposition leader Juan Guaido.

In January, Guaido declared himself acting president, claiming Maduro's re-election last year was illegitimate.

More than 50 countries led by the United States lined up behind national assembly head Guaido, but Russia and China have backed Maduro.

In early June, the Wall Street Journal said Russia has cut its staff in Venezuela to just a few dozen, from about 1,000 at the height of cooperation between Moscow and Caracas several years ago.

The pullout was due to a lack of fresh contracts and the realisation that Maduro's regime no longer has the money to pay for Moscow's services, the newspaper said.

Russia denied the report at the time.

After the report Trump tweeted that "Russia has informed us that they have removed most of their people from Venezuela," which Moscow denied.