President Nicolás Maduro has won Venezuela's presidential election, according to partial results announced by the electoral council.

The head of the National Electoral Council (CNE), Elvis Amoroso - who is a close ally of Mr Maduro - said that with 80% of ballots counted, President Maduro had 51% of the vote, compared to 44% for his main rival.

The Venezuelan opposition dismissed the CNE's announcement as fraudulent and promised to challenge the result.

It said its candidate, Edmundo González, had won with 70% of the votes and insisted he was the rightful president-elect.

The opposition said vote tallies it had received, as well as quick counts, showed Mr González had a lead of 40 percentage points over the incumbent.

Opposition parties had united behind Mr González in an attempt to unseat President Maduro after 11 years in power.

Opinion polls conducted ahead of the election had suggested Mr González would roundly defeat the president.

The result of the election will have repercussions well beyond the South American country of 29.4 million inhabitants.

Over the past 10 years, 7.8 million people have fled Venezuela because of the economic and political crisis into which the country was plunged under the Maduro Administration.

Polls conducted in the run-up to the election suggest that exodus could now increase, with one poll suggesting a third of the population would emigrate.

With immigration a hot topic in the US election, the government in Washington, as well as Latin American nations to which Venezuelans have emigrated en masse, are affected by what happens in the Andean country.

Who Venezuela does business with also matters because it has the world's biggest oil reserve.

Mr Maduro blames US sanctions for his country's economic woes and has forged close alliances with China, Iran, and Russia - nations which also have a thorny relationship with the US.

A change of government could see Venezuela turn away from these countries as well as from its close ally, Cuba, while Mr Maduro is expected to deepen his ties with his allies should he stay in power.

Many Venezuelans were adamant that they wanted change after 25 years in which the socialist PSUV party has been in power - first under the leadership of the late President Hugo Chávez, and after his death from cancer in 2013, under Nicolás Maduro.

In the queue at one polling station in Petare, a poor neighbourhood in the capital, Caracas, many people said they were voting for “change”.

“This government has had all the opportunities to make Venezuela a great country, but instead we have misery,” Héctor Emilio D’Avila told BBC reporter Ione Wells.

“Our children have to go through a jungle, the Darién Gap, to the US. There are many dead Venezuelans in the jungle. Our children are dying.”

There was widespread fear that the government could resort to fraud to win the election. Mr Maduro's win in 2018 was also widely dismissed as neither free nor fair.

However, the opposition had hoped its lead would be so convincing, it would thwart any attempts by the Maduro administration to "steal the election".

One community leader, Katiuska Camargo, said for many years people did not turn out in such large numbers because “there was so much collective disappointment" but that now people were "determined that these people leave power immediately".

US Secretary of State Antony Blinken was among those expressing his scepticism after the result was announced by the National Electoral Council, a body which is dominated by government loyalists.

He said the US had "serious concerns that the declared outcome does not reflect the will or the votes of the Venezuelan people".

The UK Foreign Office also expressed concern over the results, calling for the "publication of full, detailed results to ensure that the outcome reflects the votes of the Venezuelan people".

The Chilean president, Gabriel Boric, also said he found the result "hard to believe".

Mr Boric demanded "total transparency of the minutes and the process, and that international observers not committed to the government account for the veracity of the results".

Uruguay's president said of the Maduro government: "They were going to 'win' regardless of the actual results."

Meanwhile, allies of Mr Maduro were quick to congratulate him.

In a congratulatory message, President Vladimir Putin told Mr Maduro: "Remember, you are always a welcome guest on Russian soil."

Cuban President Miguel Díaz-Canel said "the dignity and bravery of the Venezuelan people had triumphed over pressure and manipulation".

Mr Maduro described the result as "a triumph of peace and stability" to cheering supporters in Caracas - praising the Venezuelan election system and mocking his opponents.

The opposition had deployed thousands of witnesses to polling stations across the country to be able to announce its own vote count.

However, a spokeswoman for the coalition led by Mr González said that their witnesses had been "forced to leave" many polling stations.

Voting in Venezuela is electronic. Voters punch in a button assigned to their preferred candidate on a voting machine.

The electronic results are sent to the CNE headquarters, but the machine also prints out a paper receipt which is then placed in a ballot box.

By law, parties are allowed to send witnesses to the count of these paper receipts carried out at each polling station, but many were prevented from doing so.

Their plan had been to monitor these tallies to see if they squared with the results announced by the CNE, but the opposition said late on Sunday that it had so far been given access to less than a third of the printed receipts.