In a nation awash with rumors amid a government crisis in which two men have claimed Venezuela's presidency, even the unexpected arrival of a Russian passenger jet can set off a social media frenzy.

The Boeing 777 belonging to Russia's Nordwind Airlines arrived Monday night and could still be seen Wednesday on the tarmac at Maiquetia airport outside the capital, its presence sparking unproven claims that President Nicolas Maduro's administration is looking to whisk what's left of the nation's depleted gold reserves out of the country.

A Nordwind representative confirmed the plane's arrival but wouldn't comment on who chartered the plane, what it is carrying or its itinerary. It is believed to be the first time the aircraft has flown to Venezuela. Flight data shows it normally flies inside Russia and to southeast Asia.

Opposition lawmaker Jose Guerra, a former central bank director, set off the wave of speculation with his claim Wednesday that unnamed sources inside the monetary authority informed him the plane was hired to transport 20 metric tons of gold comprising about 15 percent of the reserves held in Caracas.

"This needs to be taken with utmost seriousness," Guerra said in a speech to lawmakers.

"These reserves don't belong to Calixto Ortega, they belong to Venezuela," he added, referring to the central bank's president, a close ally of Maduro.

The Associated Press was unable to verify the authenticity of Guerra's claim. There was no immediate response from Maduro's government.

Venezuelan social media was alive with theories - that it had brought mercenaries, was there to escort Maduro into exile, or was loading up with gold. None of those theories was based on solid evidence, but the feverish speculation was a testament to the atmosphere of uncertainty in the country as Maduro comes under unprecedented international pressure to step down.

Reuters reported last week that private military contractors who carry out secret missions for Russia had flown into Venezuela to beef up Maduro's security in the face of mass opposition protests last week, according to people close to them.

The plane normally flies between Russia and Southeast Asia, according to publicly-available flight data. Neither Nordwind nor other commercial airlines offer direct Moscow-Caracas flights.

Russian newspaper Novaya Gazeta reported the plane flew with two crews and no passengers.

Maduro claims he is facing a Washington-backed coup attempt led by opposition leader Juan Guaido, who last week proclaimed himself president and was recognized by the United States as the legitimate head-of-state.

Russia has accused U.S. President Donald Trump's administration of trying to usurp power in Venezuela and warned against any military intervention. The Kremlin on Tuesday condemned new U.S. sanctions against Venezuela's vital oil sector as illegal interference in the OPEC member's affairs.