Voters in South Carolina have chosen Darline Graham, the sister of the late Senator Lindsey Graham, as the Republican candidate to contest his US Senate seat in November.

Graham's bid received strong backing from President Donald Trump, who travelled to the state to campaign for her. Graham's victory is being seen as evidence of Trump's continuing influence over the Republican Party.

Graham is currently serving in the Senate as a temporary replacement for her brother, who died suddenly in July. She had never previously run for elected office.

Republicans and Democrats also held primaries in several other states on Tuesday, as they narrowed down their field of candidates for the midterm elections.

Political experts expect that Graham will now go on to succeed in the November election. South Carolina has not elected a Democrat to the Senate for decades.

The midterms more generally will decide which party controls the US Congress - which in turn will have a bearing on the second half of Trump's presidency.

Graham was running against right-wing Republican Congressman Ralph Norman, who sought to portray his opponent as a puppet of Washington politicians.

The head-to-head was set up after the pair emerged as the top two from a wider field of candidates during an initial contest earlier this month.

Norman is a supporter of Trump and has voted in favour of many of his policies. But in 2024, he initially backed Trump's primary opponent Nikki Haley as his pick for Republican presidential candidate.

With counting almost complete, Graham had received 52.5% of the vote, according to the BBC's US partner CBS News.

In a post on X, she thanked her supporters and the president, and said she was "deeply honoured and humbled" by the result.

During her primary campaign, Graham acknowledged her lack of political experience, particularly after stumbling during a foreign-policy question during a recent debate.

Asked about the US stance towards Taiwan, Graham had said: "I'm not that informed on national security." She added: "National security is not my thing, not my area of expertise, but I do support the military."

Trump's influence over the party was also tested in Oklahoma, where Mike Mazzei, a former state lawmaker endorsed by the president, took on Gentner Drummond, the state's attorney general.

The winner is widely expected to become the next governor in the heavily Republican state.

South Carolina was not the only state that held an election on Tuesday to replace a deceased lawmaker.

In Georgia, voters in the Atlanta area were tasked with choosing a replacement for Democratic Congressman David Scott, who died in April.

Marcye Scott, the daughter of the late congressman, was among those seeking office. But projections in US media show she was beaten by opponent Everton Blair.

Blair will therefore serve out the remainder of the term, which ends in January. In November, two other candidates will run to take over his seat in the new year.