Two notable holdouts have emerged as world leaders congratulate Joe Biden on his US election victory, with the presidents of Latin America's two largest countries - Brazil and Mexico - so far remaining silent.

Brazil's Jair Bolsonaro, dubbed "the Trump of the Tropics" for his populist, off-the-cuff style, has not made any public comment on Mr Trump's loss.

And Mexican President Andres Manuel Lopez Obrador has so far refused to congratulate Mr Biden, saying he would wait until the legal challenges over the vote were resolved.

Mr Trump and the two Latin leaders are united by some surface similarities: They dislike wearing masks during the coronavirus pandemic, and all three can loosely be described as populist and nationalist. But the motives of the two Latin leaders may differ.

Mr Bolsonaro and his sons - who like Mr Trump's offspring play a political role - appeared to be actively uncomfortable with the outcome of the US race.

The Brazilian leader, who previously expressed hope for Mr Trump's re-election and whose son wore hats with the logo "Trump 2020'', has kept largely quiet this week, although his sons have not.

Congressman Eduardo Bolsonaro posted images on social media questioning how Mr Biden's votes were rising so quickly in later counts while Mr Trump's were not. The younger Bolsonaro also questioned networks' decision to cut away from Mr Trump's speech on Wednesday alleging electoral fraud, calling it an attack on free speech.

A senior official of the Brazilian Embassy in the United States, who spoke on condition of anonymity, said Brazilian officials feared loose talk by Mr Bolsonaro or his sons could destabilise relations between the two countries.

Officials in the office of the presidency, who were also not authorised to speak on the record, said Mr Bolsonaro had been adopting a more pragmatic tone, at least since Wednesday, following the guidance of his advisers.

At the beginning of the week, some of the more ideological elements in Mr Bolsonaro's office believed in a Trump victory. But since then, Brazilian diplomatic staff have made contact with Mr Biden's campaign.

Mr Lopez Obrador's cordial relationship with Mr Trump, meanwhile, was often seen as unusual for a left-leaning politician, but it had a practical basis.

In part, that is political realism: In 2019, Mr Trump threatened to apply crippling tariffs on Mexican products unless Mr Lopez Obrador cracked down on Central American migrants crossing Mexico to reach the US border. Mexico complied, rounding up migrants and busing them back to their home countries.

But there were also moments of apparent camaraderie between the two. On Saturday, Mr Lopez Obrador was one of the few world leaders still willing to heap praise on Mr Trump.

"President Trump has been very respectful of us, and we have reached very good agreements, and we thank him because he has not interfered and has respected us," Mr Lopez Obrador said.

Mr Lopez Obrador also angered many at home and in the US Democratic Party when he made his first - and so far only - trip abroad as president over the summer to meet Mr Trump to celebrate the enactment of the new US-Mexico-Canada free trade agreement, which both leaders viewed as fixing problems with the old North American Free Trade Agreement of the 1990s.

Mr Lopez Obrador did not meet with Mr Biden or his campaign team during that trip. Wounds from that decision remain apparent, even though the Mexican president said he already knew Mr Biden and had "very good relations" with him.

Representative Joaquin Castro, the Democratic congressman for Texas's 20th District, wrote in Spanish in his Twitter account that the unwillingness to congratulate Mr Biden "represents a true diplomatic failure on the part of Andres Manuel Lopez Obrador, at a moment in which the incoming Biden administration is seeking to start a new era of friendship and cooperation with Mexico".

Representative Jesus Garcia, a Democrat from Illinois' 4th District, similarly wrote to Mr Lopez Obrador that "American voters have spoken and Joe Biden is our President Elect. He won fair and square. Don't miss the boat".