Burgum, who leads President Donald Trump's National Energy Dominance Council, met interim leader Delcy Rodriguez at the presidential palace in Caracas.

The pair were expected to issue a joint statement after their talks, which reflect the dramatic shift in ties between Washington and former foe Caracas since the US ouster of longtime leader Nicolas Maduro in January.

The US charge d'affaires in Venezuela, Laura Dogu, said Burgum's visit was aimed at developing "a legitimate mining sector and secure supply chains for critical minerals."

It follows that of Energy Secretary Chris Wright on February 11.

Trump has boasted that Washington is in effective control of Venezuela since Maduro's capture in a bombing raid on Caracas that left 100 dead.

Maduro was flown to the United States, where he is due in court later this month on drug trafficking charges, which he denies.

Trump greenlighted Maduro's former deputy Rodriguez to succeed him, with the proviso that she submit to US demands on access to oil.

Washington has also pressured her administration to end the repression of political opponents.

- Rare earths -

Venezuela has the world's largest proven oil reserves, which Trump says he wants to harness for the benefit of both Venezuelans and Americans.

The Caribbean country is also rich in minerals such as gold, diamonds and coltan, which contains a metal used in mobile phones, laptops and other electronics.

Mining activity is concentrated in a vast southeastern territory known as the Orinoco arc.

Environmentalists have condemned the expansion of illegal mining in the area, saying it has caused rampant deforestation and river pollution.

After overhauling the oil sector to woo foreign investors, with input from Washington, Rodriguez has set her sights on reforming the country's mining legislation.

Few details have been revealed so far but her brother, congress speaker Jorge Rodriguez, said Monday the reform would allow "large foreign companies" to exploit minerals and rare earth elements.

Burgum's visit came a day after Venezuelan state oil firm PDVSA announced the signing of new oil contracts with the United States.

The new supply deals come amidst fears of a fall in global oil output due to the war in the Middle East, which has already pushed crude prices to their highest levels in a year and a half.

So far PDVSA has shipped more than 80 million barrels of crude to the United States, according to Trump.