Let's take a look at some of today's polling spots.

Image source, Reuters

Image source, Reuters

Image source, Reuters

Image source, Reuters

Image source, Reuters

Officials in New York are reporting problems with ballot scanners in Westchester County, but add that votes will still be counted.

Westchester County Government says the issue involves paper ballots "preventing voting machines from accepting ballots at polling locations throughout the county".

However, it adds in a post on X that it wants to "reassure every voter that your vote matters, your ballot will be secure and your vote will be counted".

Westchester County Government says its board of elections is in "constant communication" with New York state officials to address the issue, and voters should continue to complete their paper ballots as instructed by poll workers.

Polls are continuing to open across the US, with polling stations opening at 9:00 ET (14:00 GMT) in Montana, Nebraska, New Mexico, Utah, Wyoming and Colorado.

Results will start coming in later this evening - stick with us for the latest news and analysis.

Image source, AP Photo

Bernd Debusmann Jr
White House reporter in Washington DC

Image source, AFP via Getty Images

It's an unusually quiet morning at the White House, where I'm one of only a very small handful of reporters currently here. Most will come in later today, and many members of the White House press corps are on the road.

President Trump, however, appears to be busy, posting endorsement after endorsement on Truth Social. A short time ago, he also phoned into Fox News for a brief telephone interview as Americans head to the polls.

In the interview, he made yet another pitch to voters and pointed to what he said were signs of economic progress under his administration, including an end to taxes on tips and overtime and foreign investment figures.

He also claimed he was in "total control" of the Middle East and Strait of Hormuz.

The president makes similar comments very frequently, but polls show that they have largely not resonated with American voters.

Polls have consistently shown that the economy is the single biggest driver for voters in this midterm, and that many Americans - including Republicans - have grown disenchanted with the administration's handling of the economy.

High prices are a particular concern, and many voters have pointed to the war in Iran as a reason.

On Fox, Trump dismissed these concerns, and expressed optimism about the midterm's results.

"We have indeed made America great again," he said.

The president has a number of events on his schedule today, including an election night reception in the east room of the White House. As things stand, every event he has planned today is closed to the press.

Image source, Getty Images

From fiery town halls in Maine to debate stages in California, these are the issues that kept coming up and seem likely to shape voters’ minds as they cast their ballots today:

• Cost of living: Many Americans have grown weary with the high energy prices, partly brought on by tariffs and the war with Iran, that are driving up costs on petrol and other everyday purchases
• Immigration: Republicans say Trump has delivered on his pledge to tighten the border as immigration numbers are down sharply since he took office. But some are worried that the crackdown has gone too far
• Iran war: The conflict became increasingly unpopular as its consequences reverberated around the world and ultimately hit American consumers in the pocket, though some voters praised Trump for taking decisive action against Iran

• Data centres: The strong public backlash against these centres in parts of the US is uniting voters from across the political spectrum, with both Republicans and Democrats coming out against their development
• Healthcare: Many Democratic candidates are focusing on the high costs of health insurance, with some making it central to their campaigns. Republicans, however, point to Trump's efforts to bring down the cost of prescription drugs

Polls have opened in the southern state of Arkansas at 08:30 eastern time (13:30 GMT).

Americans have been turning out at polling stations across the US east coast to cast their votes so far on Tuesday, with individual state governments deciding on what time their polls open.

Here's a reminder of the key states in these elections..

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Around 1,000 election monitors and observers are being deployed to all 50 states for the first time in US history, says the US Department of Justice (DOJ).

The monitors will be used to check federal voting laws are being followed in support of "free and fair elections", according to the DOJ.

Previous administrations have monitored elections in this way but not on the same scale.

During the 2022 midterms, the DOJ under President Biden sent monitors to 24 US states.

Samira Hussain
Reporting from Des Moines, Iowa

Polls have opened here in Des Moines, Iowa where Democrats are hoping to flip this reliably red state, blue.

This election is a referendum on President Donald Trump's second term in office.

Trump is not on the ticket but has been urging his supporters to vote as if he was.

But many people are dissatisfied, citing the economy and the high cost of living as the main issues.

Democrats have been laying the blame for the country's economic woes with the current administration. Republicans have been countering that message, saying a vote for Democrats is a vote for radicals and extremists.

Already 58 million Americans have cast a ballot in early voting across the country, a record turnout for a midterm election.

Polls have just opened in Iowa, Alabama, Kansas, Oklahoma, South Dakota, Texas, Wisconsin, Arizona, Mississippi, North Dakota.

Now, we wait on the rest of the country as polls in Hawaii, for example, will only open at 13:00 eastern (18:00 GMT).

Election officials in Florida are temporarily relocating 19 polling stations because of flooding across the state.

On Monday, Florida Governor Ron DeSantis issued an executive order declaring a state of emergency in multiple counties.

The order allows election supervisors to change polling stations when the original sites become unsafe or inaccessible to voters, according to the BBC's US news partner CBS.

Florida's Division of Emergency Management says it's providing pumps, generators, and other resources to flood affected areas across the state.

Image source, Forida Division of Emergency Management/ X

Bernd Debusmann Jr
White House reporter

Image source, Reuters

As the weeks and months of midterm campaigning have gone on, Trump has repeated a plea to voters in nearly every campaign rally: "Pretend I'm on the ballot."

Trump, essentially, is hoping for a repeat of the 2024 presidential election, in which the personal loyalty of millions of voters – and dissatisfaction with President Joe Biden and the Democrats – swept him and the Republicans back into the White House and control of Congress.

The president, however, is not on the ballot and his career in formal politics will come to an end at the end of his term. His strategy – attempting to nationalise thousands of local and state elections – is an unusual one.

Clearly, he believes that voter enthusiasm for him, personally, will carry Republican candidates to victory and stop what he has repeatedly acknowledged is a historical trend in which incumbent parties take a drubbing in the midterms.

Polling day has just begun but many early birds have already cast their votes.

Image source, Reuters

Image source, Reuters

Image source, Reuters

Image source, Reuters

Republicans currently control both the House of Representatives and the Senate.

Polls suggest Democrats could win a majority of seats in the House.

But the race for a majority in the Senate is much less certain. These are the key states that will decide which party is in charge for the next two years:

• Alaska: Republican Dan Sullivan's re-election bid is being challenged by Democrat Mary Peltola and independent candidate Daniel J Sullivan
• Maine: Susan Collins is running for a sixth term against Democrat Troy Jackson
• Texas: No incumbent is in this race, setting up a highly anticipated contest between Democrat James Talarico and Republican Ken Paxton
• Kansas: Megachurch pastor Adam Hamilton is the Democratic challenger to incumbent Republican Roger Marshall in an unexpectedly close race to represent a state that for decades has reliably voted Republican
• Michigan: With no incumbent in the race, Michigan's race is among the most closely watched. Democrat Abdul El-Sayed could become the first Muslim US senator, but he faces a strong challenge from Republican Mike Rogers

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Polls have just opened in Florida, Delaware, Georgia, Illinois, Louisiana, Maryland, Massachusetts, Michigan, Missouri, Pennsylvania, Rhode Island, South Carolina, Washington DC.

Individual state governments decide on what time their polls open.

A little earlier, polling stations opened across the east coast - including in swing states Maine and Ohio.

As polls are opening across the US, some 58,677,062 votes have already been cast, as of 23:30 eastern time (04:30 GMT) on Monday.

According to data published by the Election Lab at the University of Florida, 31,897,521 were in-person early votes and 26,779,541 were mail ballots.

More US states have offered early voting in recent years. The Center for Election Innovation & Research says that 97% of eligible voters in the US live in areas where this is an option.

Image source, Reuters

Jack Grey
Live reporter

Image source, Getty Images

Democratic Congresswoman Haley Stevens has defended her decision to endorse the Republican candidate for the key Senate seat of Michigan, Mike Rogers.

Stevens, who lost out on the Democrat nomination to El-Sayed, has been heavily criticised by members of her party for the move.

In an 890-word post on X last night, Stevens ran through her reasons for endorsing Rogers, including:

• Political ads: Stevens identifies attack ads on Mike Rogers, both unofficial and from the El-Sayed campaign, which she says are not the way to "bring people together"
• Hasan Piker: She criticises El-Sayed's association with the left-wing political commentator and streamer
• 'Shut out': Stevens says she was told she was not welcome at El-Sayed's campaign events, which, she says, raises questions as to how he can "represent an entire state filled with people who disagree with him"

Sakshi Venkatraman
US reporter

The political party that controls Congress has the power to shape the laws of the US – laws that affect Americans from coast to coast.

Currently, Trump's Republican Party has power in the White House and both chambers of Congress – the House and the Senate. Their majority is slim, but it means they have the power to bring their preferred laws to the floor and have them signed off by the president.

The Democratic Party opposition wants to change that.

It's now 06:30 in North Carolina, Ohio and West Virginia and polls have just opened.

While results won't come in until much later, Ohio is on our list of US Senate races to watch closely in these midterm elections.

It's just gone 06:20 US eastern time and voters are beginning to spill into a sports hall in Manchester, New Hampshire, to cast their ballots.

Image source, Reuters

Image source, Reuters

Sarah Smith
North America editor

Image source, Getty Images

With two years of his presidency remaining, Donald Trump, who has dominated American politics over the past decade and transformed it in remarkable ways, is facing potentially pivotal elections.

Voters overwhelmingly say they are most concerned about the cost of living. Food and fuel prices have soared in part due to the president's aggressive tariffs and unpopular war with Iran, so it will be top of mind as many head to the polls.

Trump, who has faced record low approval ratings in recent months, has been campaigning hard, headlining dozens of rallies across the country.

But high prices are a concern for voters on all sides – which helps explain why he has been campaigning in previously safe Republican territory, appearing in Iowa and Kansas during a final weekend blitz.

His party has also poured hundreds of millions of dollars of campaign advertising into these traditionally safe contests, such as the Senate race in Kansas.

• The BBC's North America editor Sarah Smith has more analysis ahead of today's pivotal elections