And, as senate Republicans still refuse to acknowledge the election outcome, so have some world leaders repeated claims that results remained undecided, or “won” by president Trump.
Here are those still yet to send congratulations:
Russian president Vladimir Putin
The Russian president will not congratulate Joe Biden while Donald Trump’s campaign launches legal challenges in US courts, a spokesman said on Monday.
President Putin, who has not sent any message to the Democrat, did not wait to delay congratulating Mr Trump four years ago.
As president, Mr Trump has rarely criticised his Russian counterpart, who was accused of helping him get elected last time around.
Mr Biden has been more vocal, alleging last October that "the main threat" to US national security was Russia, in an interview with CBS.
Brazilian president Jair Bolsonaro
Another ally to the American president, Jair Bolsonaro, referred to president-elect Biden as a “candidate” when he addressed the US election on Tuesday.
Mr Bolsonaro, still to make a public statement, told a Brazilian audience that the Democrat had been a “a great candidate” and complained about his calls for better protection of the Amazon rainforest.
“When saliva runs out, one has to have gunpowder, otherwise it doesn’t work,” Mr Bolsonaro was reported to have said, as per Reuters.
The so-called “Trump of the Tropics" was believed to have planned to wait until the outcome of legal challenges before commenting further.
Slovenian prime minister Janez Jansa
The Slovenian prime minister tweeted premature congratulations to Mr Trump last Wednesday, as votes continued to be counted.
“It’s pretty clear that American people have elected Donald Trump and Mike Pence for four more years,” wrote Mr Jansa, who attacked “mainstream media” denial in the same message.
The Slovenian Democratic Party leader, however, struck a softer tone on Saturday, when US media outlets did call the presidency for Mr Biden, saying America was a strategic partner.
The far-right anti-immigration politician hails from the same county as Melania Trump, the US president’s wife.
Mexican president Andrés Manuel López Obrador
Despite tensions over migration and a border wall, Mr López Obrador has maintained strong relations with Mr Trump, and so avoided accepting his American counterpart’s election defeat.
Instead, the Mexican president issued a carefully worded statement in which he said he would wait until Trump campaign legal challenges had concluded.
"We are going to wait for all the legal issues to be resolved. We do not want to be reckless. We do not want to act lightly. We want to be respectful of the self-determination of the people and of their rights," said Mr López Obrador on state television on Saturday.
While he added that Mexico had a "very good relationship" with both candidates, he has not congratulated president-elect Biden.
Chinese president Xi Jinping
Both Xi Jinping and China have been a source of consternation for Mr Trump, whose administration has waged a trade war and oversaw tense relations as the coronavirus pandemic impaired his re-election chances.
Still, there was no warmth for Mr Biden either, following his election victory last week - even though the US president was congratulated by the Chinese premier as soon as polls showed he’d won four years ago.
In a short statement on Monday, the country’s foriegn ministry said “we have noticed Joe Biden has declared victory, we understand the presidential election result will be determined following US law and procedures”.
Mr Biden has promised to take on China, and denounced Mr Trump’s past attempts at embracing president Xi.
North Korean leader Kim Jong-un
Pyongyang has been silent on Mr Biden’s election win last week, with no message delivered to the president-elect, and no reported mention of the contest on North Korean state media.
Jong-un, while two days late to acknowledging Mr Trump’s success four years ago, appears to be waiting even longer this time around.
Labelled "rocket man" by the US president, the pair met on three occasions and exchanged a series of personal letters.
Despite those relations, the reclusive country showed little movement toward shrinking its nuclear weapons programme. All the while, US sanctions remained in place.
Mr Biden called Mr Kim "a murderous dog" last year, to which the North Korean leader responded that the Democrat was a "rabid dog" who should be "beaten to death with a stick".
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