A defiant Maduro was sworn in for a new presidential term Friday in a ceremony decried as illegitimate by the opposition and internationally, with Washington offering a $25 million reward for his arrest.

Washington and London have imposed sanctions on Maduro's regime, and only two prominent regional leaders -- Cuban President Miguel Diaz-Canel and Nicaraguan ex-guerrilla Daniel Ortega -- attended his inauguration.

Russian President Vladimir Putin sent his congratulations, but traditional left-wing allies, including Brazilian President Luiz Inacio Lula da Silva, pointedly stayed away.

Xi's envoy, Wang Dongming, met with Maduro at the presidential palace after the ceremony.

"Wang conveyed cordial greetings and good wishes from Xi to Maduro and congratulated him on his re-election as president of Venezuela," Xinhua reported.

The pair reinforced China and Venezuela's "all-weather strategic partnership," with Wang reportedly saying that Beijing is willing to "develop" their friendship and "push forward" bilateral relations.

"Maduro asked Wang to convey his highest respect and sincere greetings to Xi," the report continued.

Venezuela "stands ready to join hands with China to ... lift bilateral ties to a new level," Maduro said, according to Xinhua.

On Friday, Maduro's challenger in July's election, Edmundo Gonzalez Urrutia, recognized by the United States and much of Latin America as the legitimate winner, said Maduro had "crowned himself a dictator" and staged a "coup."

The US reward relates to narco-trafficking charges dating to 2020, two years after Maduro's first re-election in a vote also tainted by fraud allegations.

Maduro, a former bus driver and trade unionist, has clung to power for over a decade through a mix of populism and repression.

His third term could see him remain in office until 2033.

The opposition is now waiting to see how US President-elect Donald Trump will deal with Maduro on his return to the White House later this month.