Venezuela's opposition leader Juan Guaido on Wednesday visited the White House like a head of state, but President Donald Trump's impeachment drama overshadowed the moment.

Guaido, who with U.S. support has been seeking for more than a year to topple leftist president Nicolas Maduro, pulled up to the White House in a black SUV as Trump gave a thumbs-up sign to the cameras, in front of Marine sentries stationed at the doors.

But the White House abruptly canceled a press conference in the Oval Office, which had been scheduled to take place shortly before the Senate voted for the removal of Trump from office.

While Trump's acquittal had been widely expected, he was deprived of a complete party-line vote, when Republican Senator Mitt Romney revealed he would vote to convict the president.

Despite Washington's focus on impeachment, which stemmed from Trump's pressure on Ukraine to dig up dirt on a political rival, Guaido appeared buoyed by the support.

Guaido, writing on Twitter after meeting earlier in the day with Vice President Mike Pence, said he was working together with the United States "for the freedom of Venezuela."

"We appreciate the firm and clear fight from the U.S. government together with the Venezuelan people and our region," Guaido tweeted.

Guaido, a 36-year-old engineer turned politician, is considered interim president by the United States and most other Western and Latin American nations.

Trump – who some observers had thought was no longer interested in Venezuela – on Tuesday forcefully called for Maduro's ouster, during his annual State of the Union address to Congress.

'Humiliating crumbs' 

Venezuela's government lashed out both at Trump and Guaido, who has been allowed to move with relative freedom despite a travel ban and his seeking to overthrow the regime.

"Trump offends and disrespects the Venezuelan people by proffering violent threats against its integrity and against the constitutional, legitimate and democratic government of President Nicolas Maduro," Foreign Minister Jorge Arreaza told reporters in Caracas.

A separate government statement hit out at Guaido, denouncing the "shameful complicity of those dedicated to selling their homeland for humiliating crumbs tossed to them by their boss, Mr. Trump."

(With input from AFP)