A day after Americans voted in a bitterly contested election, the rest of the world was none the wiser yesterday, with millions of votes still to count, the race too close to call and a mounting risk of days or even weeks of legal uncertainty. 

Donald Trump's pre-emptive declaration of victory at the White House was condemned by some US political commentators and civil rights groups, who warned about the trampling of long-standing democratic norms.

Most world leaders and foreign ministers sat on their hands, trying not to add any fuel to the electoral fire.

"Let's wait and see what the outcome is," said British Foreign Secretary Dominic Raab. "There's obviously a significant amount of uncertainty. It's much closer than I think many had expected."

But while Raab and others urged caution, the Slovenian prime minister broke ranks, congratulating Trump and the Republican party via Twitter.

"It's pretty clear that American people have elected @realDonaldTrump and @Mike_Pence for #4moreyears," wrote Janez Jansa, one of several east European leaders, including Hungary's Viktor Orban, who are fervent Trump allies.

The latest vote tally showed Democrat challenger Joe Biden with a lead in the Electoral College - 224 votes to 213, with 270 needed for victory - but with counting still be completed in at least five major 'battleground' states: Pennsylvania, Michigan, Wisconsin, North Carolina and Georgia.

On Twitter, the hashtags #Trump, #Biden and #USElections2020 were trending from Russia to Pakistan, Malaysia to Kenya and across Europe and Latin America, underscoring how much every region of the world sees the outcome as pivotal.

In Russia, which US intelligence agencies have accused of trying to interfere in the election, there was no official reaction.

In Australia, crowds watched the results roll in while drinking beer in an American bar in Sydney. Some supported Trump, while others were quick to underline the ramifications of the US vote worldwide.

"I think it affects us all, what happens over there really matters for the next four years over here," said Sydney resident Luke Heinrich.

China said the election was a domestic affair and it had "no position on it".

Chinese social media users, however, were quick to mock the failure of the US electoral system to deliver a quick and clear result. "Whether he wins or loses, his final mission is to destroy the appearance of American democracy," one user on China's Twitter-like Weibo platform wrote on Wednesday. "Let Trump be re-elected and take the US downhill," another wrote.

In Nigeria, one leading politician, Senator Shehu Sani, said the uncertainty in the United States was reminiscent of Africa.

"Africa used to learn American democracy, America is now learning African democracy," he tweeted to his 1.6 million followers.

In Iran, President Hassan Rouhani said the result of the US election was not important for the country's clerical rulers, but that the next president in Washington should respect international treaties and laws.

"For Tehran, the next US administration's policies are important and not who wins the US election," Rouhani said.