The US presidential election reached a climax on Tuesday as Democratic Vice-President Kamala Harris and Republican former president Donald Trump vied for the 270 Electoral College votes needed to win the White House.

After weeks of early voting and mail-in ballots, the divisive campaign culminated with the conclusion of voting on Election Day.

As of 11:55 pm ET, Trump held a lead in electoral votes with 230, while Harris had 200, after getting a boost from California's 54 electoral votes, according to The New York Times.

Trump had roughly 59 million votes nationally to about 55 million for Harris, CNN reported.

In the 100-member Senate, which Democrats currently control, Republicans held a 49-40 advantage.

In the 435-member House of Representatives, currently controlled by Republicans, they held a 169-125 lead.

The Associated Press has called the outcome in several states, based on vote projections.

The AP called the reliably red (Republican) states of Alabama, Arkansas, Florida, Idaho, Iowa, Kansas, Louisiana, North Carolina, North Dakota, South Dakota, Mississippi, Missouri, Montana, Ohio, Oklahoma, South Carolina, Tennessee, Texas, Utah and Wyoming for Trump.

A Des Moines Register poll over the weekend had Harris leading in Iowa, which Trump won in 2020.

Harris was projected to win the usually blue (Democratic) states of California, Connecticut, Delaware, Illinois, Maryland, Massachusetts, New Jersey, New Mexico, New York, Oregon, Rhode Island, Vermont, Virginia and Washington.

The key northern swing states of Pennsylvania, Michigan and Wisconsin were considered too close to call but they were leaning toward Trump, according to the Times.

Trump also had a significant lead in Georgia, a highly contested state that President Joe Biden won by under 12,000 votes over Trump in 2020.

The contest was close in the pivotal Western state of Arizona.

"The Arizona early vote has been counted, and it shows a very close race, but Trump will probably win the Election Day vote by a wide margin. To have any chance of winning the state, Harris would need a decisive victory in the late mail ballots tabulated after Election Day," Nate Cohn reported in the Times.

With slightly less than 60 percent of the expected vote counted at 10:45 pm ET, Trump led Harris by just over 110,000 votes, the AP reported. He was winning central and northeastern Pennsylvania, but Philadelphia and its neighboring counties, which have historically been Democratic, hadn't reported all their votes yet.

Earlier Tuesday, there were reports of some voting-related problems around the US, and officials and judges were addressing them.

In Georgia, a state judge decided that five voting locations could remain open after their 7 pm ET closing times "due to evacuation necessitated by a bomb threat", the Times reported.

After some unsubstantiated threats, according to Brad Raffensperger, Georgia's secretary of state, Judge Ural Glanville of Fulton County Superior Court ruled Tuesday that each metro Atlanta polling site could stay open for as long as it was closed while the threats were being investigated. The five locations around metropolitan Atlanta were expected to remain open from 15 minutes to 45 minutes more, the Times reported.

As voters went to the polls, about 7 in 10 voters said they were "very concerned" about the impact of the cost of food and groceries on their household budgets, according to AP VoteCast.

Agencies contributed to this story.