In an unprecedented claim in US politics, Donald Trump on Wednesday falsely asserted "fraud" in the counting of votes and said he would approach the Supreme Court to stop it, as the race between the incumbent Republican President and his Democratic challenger Joe Biden was poised for a photo-finish.

In one of the most divisive and bitter presidential contests in American history, the election saw tight races in many key battleground states with Biden winning 224 electoral college votes and Trump closely behind with 213. The winner of the 2020 presidential election should have at least 270 electoral college votes out of the 538-member electoral college.

The field of battle, reported The New York Times, had dwindled to the trio of northern states Pennsylvania, Michigan and Wisconsin _ the vey states that pushed Trump towards victory against Hillary Clinton in 2016, as well as Arizona and Nevada, where Biden had narrow leads, and Georgia, where he trailed but was gaining ground with every vote count.

It was a fight to finish with Trump declaring victory prematurely and even threatening to move the Supreme Court to demand a halt to counting. Biden, true to character, urged supporters to show patience and allow the entire process to play out.

The final outcome, as when it is revealed, hinges on uncertainties. For one, it could be days before a winner is announced, both The New York Times, The Guardian and television channels noted. Here are some key takeaways:

Days of wait

Election officials in Wisconsin, Pennsylvania and Michigan in particular have all warned that it could take days for the counting to finish and for clear election results to emerge.

Also, if progressives hoped that a Biden win would be coupled with a Democratic takeover of the Senate, it was not so. By early Wednesday, Republicans managed to win some major challenges. Several key Senate races remain in play, though look favourable to Republicans, boosting their chances of protecting their majority. Democrats remained favoured to control the House, and some polls have suggested they could extend their majority.

No landslide

Democrats had hoped for a decisive victory for Biden based on his strong polling lead in key battlegrounds. But by early Wednesday morning, it was clear that a fight for an electoral college win was going to be closer than expected. Crucially, Trump won Florida (29 electoral votes), which was essential for him to remain in the race.

Midwest will be key

With Trump holding on to Florida, Ohio and Iowa, the campaigns are closely following the counts in the key battleground states in the Midwest that are currently too close to call. Biden said he was “feeling real good” about Michigan (16 votes) and Wisconsin (10 votes), two states that played a decisive role in Trump’s 2016 victory. He also said he was optimistic about Pennsylvania (20 votes), one of the largest states to swing to Trump in 2016 when it went Republican for the first time since 1992.

Arizona could pave the way for Biden

The last time Arizona voted for a Democrat was in 1996, but the state has become more competitive in recent years. The loss for Trump in this state (11 votes) narrows his potential pathways to victory.

Earlier in the day, Trump called the election "a fraud on the American public" and said, "Frankly, we did win this election." He also said he planned to take the battle to the Supreme Court to stop the counting of votes.

"All of a sudden everything just stopped. This is a fraud on the American public. This is an embarrassment to our country. We were getting ready to win this election. Frankly, we did win this election," Trump said, without citing any evidence of a fraud in the electoral process.

"We will win this, and as far as I'm concerned, we already have won it," Trump, 74, said in remarks to supporters in the White House East Room at 2 am.

"We want all voting to stop. We don't want them to find any ballots at four o'clock in the morning and add them to the list," Trump said, amidst applause from his supporters.

Reacting sharply, Biden's campaign manager called Trump's statement as "outrageous, unprecedented, and incorrect."

"If the president makes good on his threat to go to court to try to prevent the proper tabulation of votes, we have legal teams standing by ready to deploy to resist that effort. And they will prevail," Jen O'Malley Dillon said.

"The president's statement tonight about trying to shut down the counting of duly cast ballots was outrageous, unprecedented, and incorrect. It was outrageous because it is a naked effort to take away the democratic rights of American citizens," Dillon said in a statement.

Polls before the Election Day suggested possible outcomes ranging from a comfortable win for Biden, to a narrow victory for Trump where he loses the national popular vote but once again carries enough battleground states to win in the electoral college.

But Trump's decision to move the Supreme Court brought in added uncertainty to the contest with the mainstream American media criticising the president.

"No elected leader has the right to unilaterally order votes to stop being counted, and Mr. Trump's middle-of-the-night proclamation amounted to a reckless attempt to hijack the electoral process as results in key battleground states were still not final," The New York Times commented, criticising the president's move.

A short time before Trump spoke, Biden, 77, addressed supporters in his home state of Delaware. Biden projected optimism but asked voters for patience. He pointed to Pennsylvania and Michigan, among other battlegrounds, as slow-counting states that he expected to win.

"As I've said all along, it's not my place or Donald Trump's place to declare who's won this election, Biden said. "That's the decision of the American people. But I'm optimistic about this outcome."

"It ain't over till every vote is counted," Biden added.