Despite the recent release of a US prisoner and his wife on Saturday, sanctions will continue to exist on Venezuela, US Vice President Mike Pence said.

American missionary Josh Holt, held by Venezuela without trial on weapons charges since 2016, returned home with his wife on Saturday after the South American country's socialist government unexpectedly released them.

They were welcomed to the White House by US President Donald Trump, who told Holt he had been "incredibly brave."

"It's amazing that you were able to take it ... that was a tough situation," Trump said during a televised meeting at the Oval Office with Holt's parents.

The freeing of the Mormon missionary from Utah came despite deepening US-Venezuelan tensions that in the last week saw tit-for-tat expulsions of diplomats, Washington's refusal to recognize the May 20 re-election of Venezuelan President Nicolas Maduro, and the imposition of new US sanctions on Caracas.

Holt, who was arrested in June 2016 while he was in the country for his wedding to his Venezuela-born wife, said he was "overwhelmed" to be back home after two very difficult years.

"I'm just so grateful for what you guys have done, and for thinking about me, and caring about me, just a normal person," Holt said during the Oval Office meeting. "It really touches me," he said, his voice breaking.

The couple were accompanied home by US Senate Foreign Relations Committee Chairman Bob Corker, who met on Friday with Maduro.

Utah Senator Orrin Hatch, who was also at the Oval Office meeting, said earlier on Saturday in a statement that Holt's release followed two years of intense lobbying, working with two presidential administrations, countless diplomatic contacts around the world, and Maduro himself.

"You better really live a good life," Hatch told Holt at the White House, drawing chuckles from Holt's family and others.

In a statement, Holt's relatives gave thanks "to all who participated in this miracle."

A source familiar with the issue who asked to remain anonymous said there was no quid pro quo or agreement to ease US sanctions tied to Holt's release, and that Trump was not involved in the final negotiations.

SANCTIONS TO STAY

"Very glad that Josh Holt is now back home with his family – where he has always belonged," US Vice President Mike Pence wrote on Twitter. "Sanctions continue until democracy returns to Venezuela."

He was echoed by Secretary of State Mike Pompeo, who said US policy remains unchanged. "The United States stands steadfast in support of the Venezuelan people and their efforts to return to democracy," Pompeo said in a statement.

At a news conference in Caracas earlier on Saturday, Venezuelan Communications Minister Jorge Rodriguez said Holt and his wife were freed as part of efforts by Maduro's government to maintain "respectful diplomatic relations" with Washington.

"This type of gesture ... allows us to consolidate what has always been our standpoint: dialogue, agreement, respect for our independence, respect for our sovereignty," Rodriguez said.

Holt and his wife had been charged with espionage, violence and spreading activities against Venezuela's constitutional order, he said.

Matt Whitlock, a spokesman for Hatch, said the Utah Republican called Maduro last week after hearing of riots by inmates at the intelligence agency headquarters where Holt was held. In a Facebook post during the uprising, Holt had pleaded for freedom and said people were trying to break into his cell to kill him.

"Josh had posted videos and pled for help so Senator Hatch made one final plea directly to President Maduro that set wheels in motion," Whitlock wrote in an email to Reuters. "Chairman Corker went down mid-week to close the deal, and his staff have been instrumental in moving the ball forward."

Holt was held without trial at the headquarters of intelligence agency Sebin, a Caracas complex known as the Helicoide.

His family says Holt was framed on the weapons charges and the United States accused Caracas of using him as a bargaining chip in sanctions talks.

In televised comments earlier this month, the No. 2 official in Venezuela's ruling Socialist Party, Diosdado Cabello, described Holt as "the head of US espionage in Latin America" and said that he would remain behind bars.

The United States accuses Maduro's government of stifling democracy, repressing the opposition and massive corruption. Maduro says Washington is conspiring to topple him and seize the OPEC member's large oil reserves.

He blames a US "economic war" for Venezuela's fiscal woes, including hyper-inflation and food and medicine shortages that have triggered mass emigration.