Two Republican candidates are jostling to be their party's presidential nominee for the 2024 general election, while President Joe Biden is the Democratic Party's presumptive nominee, and several third-party hopefuls have joined the fray.

Here is a list of the candidates.

Republican Party:

Republican former President Donald Trump speaks at a primary election night party in Nashua, NH, Jan 23, 2024. (PHOTO / AP)

Donald Trump

Trump has embraced his indictments in four separate criminal cases - unprecedented for a former American president - and leveraged them to boost his popularity among Republicans and raise funds, helping to make him the Republican frontrunner with 49 percent in the latest Reuters/Ipsos polling. He won the party's first nominating contest in Iowa, taking more than half the votes.

Trump, 77, has called the indictments a political witch hunt to thwart his pursuit of a second four-year term, an assertion that the Justice Department has denied. If elected again, Trump has vowed revenge against his perceived enemies and has adopted increasingly authoritarian language, including saying he would not be a dictator except "on day one."

He has promised other sweeping changes, including gutting the federal civil service to install loyalists and imposing tougher immigration policies such as mass deportations and ending birthright citizenship.

Republican presidential candidate former UN Ambassador Nikki Haley speaks during a campaign event at the Hollywood American Legion Post 43, Wednesday, Feb 7, 2024, in Los Angeles. (PHOTO / AP)

Nikki Haley

A former South Carolina governor and Trump's ambassador to the United Nations, Haley, 52, has emphasized her relative youth compared to Biden, 81, and Trump, as well as her background as the daughter of Indian immigrants.

Haley has gained a reputation in the Republican Party as a solid conservative who has the ability to address issues of gender and race in a more credible fashion than many of her peers. She has also pitched herself as a stalwart defender of American interests abroad, and has argued Trump's management style is too chaotic and divisive to be effective.

She earned 12 percent support among Republicans, according to the Reuters/Ipsos survey and placed third in Iowa behind Florida Governor Ron DeSantis, who dropped out on Sunday.

Democratic Party:

President Joe Biden walks with his food order from the take out window of Cook Out, a burger joint in Raleigh, NC, Jan 18, 2024. (PHOTO / AP)

Joe Biden

Biden, already the oldest US president ever, will have to convince voters he has the stamina for another four years in office, amid concerns about his age and poor approval ratings.

Biden allies say he believes he is the only Democratic candidate who can defeat Trump. The most recent Reuters/Ipsos poll put him at 35 percent, the same level of support as Trump.

In announcing his candidacy, Biden declared it was his job to defend American democracy, and referred to the deadly Jan 6, 2021, attack on the US Capitol by Trump supporters. Vice-President Kamala Harris is again his running mate.

The economy will factor in his reelection campaign. While the US escaped an anticipated recession and is growing faster than economists expected, inflation hit 40-year highs in 2022 and the cost of food and gas is weighing on voters.

Biden has led the response of Western governments to Ukraine conflict, persuading allies to sanction Moscow and support Kyiv, and he has been supportive of Israel in its conflict with Hamas militants in Gaza.

However, he has faced sharp criticism from some within his party for failing to back calls for a ceasefire in the Palestinian territory, where Gaza health officials say more than 25,000 people have been killed, thousands of buildings have been damaged or destroyed and residents have insufficient food, water and medical supplies.

At home, he has pushed through massive economic stimulus and infrastructure spending packages to boost US industrial output, although he has received little recognition from voters for the latter.

Biden's handling of immigration policy has been criticized by Republicans and Democrats as migrant crossings at the US-Mexico border hit record highs during his administration.

Democratic presidential candidate Rep Dean Phillips, D-Minn, speaks at South Carolina's "First in the Nation" dinner at the South Carolina State Fairgrounds in Columbia, SC, Jan 27, 2024. (PHOTO / AP)

Dean Phillips

Dean Phillips, a little-known US congressman from Minnesota, announced in October he would mount a long-shot challenge to Biden because he does not believe the president can win another term.

The 55-year-old millionaire businessman and gelato company co-founder announced his bid in a one-minute video posted online, saying: "We've got some challenges. ... We're going to repair this economy, and we are going to repair America."

Independents:

Robert F. Kennedy Jr, an independent candidate for president, announces he has qualified for the 2024 presidential ballot in Utah, Jan 3, 2024, at a campaign event in Salt Lake City. (PHOTO / AP)

Robert F. Kennedy Jr

An anti-vaccine activist, Robert F. Kennedy Jr, 70, is running as an independent after initially challenging Biden for the Democratic nomination, but he is far behind in polling.

But recent Reuters/Ipsos polls show that Kennedy could harm Biden more than Trump in the presidential election, where third-party candidates have affected the outcome of US elections even without winning. He won the backing of 18 percent of respondents when included as an option in the latest survey.

He is the son of US Senator Robert F. Kennedy, who was assassinated in 1968 during his own presidential bid. Kennedy was banned from Instagram for spreading misinformation about vaccines and the COVID-19 pandemic but was later reinstated.

He lost a legal bid to force YouTube owner Google to reinstate videos of him questioning the safety of COVID vaccines.

In this file photo dated Feb 10, 2020, Harvard Professor Cornel West speaks at a campaign rally for Democratic presidential candidate Sen. Bernie Sanders, I-Vt, at the Whittemore Center Arena at the University of New Hampshire in Durham, NH. (PHOTO / AP)

Cornel West

The political activist, philosopher and academic said in June he would launch a third-party bid for president that is likely to appeal to progressive, Democratic-leaning voters.

West, 70, initially ran as a Green Party candidate, but in October he said people "want good policies over partisan politics" and announced his bid as an independent. He has promised to end poverty and guarantee housing.

In this file photo dated Oct 2, 2019, former Green Party presidential candidate Jill Stein waits to speak at a board of elections meeting at City Hall, in Philadelphia. (PHOTO / AP)

Jill Stein

Jill Stein, a physician, re-upped her 2016 Green Party bid on Nov. 9, accusing Democrats of betraying their promises "for working people, youth and the climate again and again - while Republicans don’t even make such promises in the first place."

Stein, 73, raised millions of dollars for recounts after Trump's surprise 2016 victory. Her allegations yielded only one electoral review in Wisconsin, which showed Trump had won.