In a post on his official X account, external, he said Graham had visited the country 10 times since Russia's full-scale invasion and was "with our people when it was most needed".

"America and the world have lost a determined leader," he added.

Graham initially clashed with the US president.

He told CNN in 2015 that Trump was "a race-baiting, xenophobic, religious bigot", and during the 2016 campaign he posted on social media: "If we nominate Trump, we will get destroyed... and we will deserve it."

After the US Capitol riots in 2021, Graham gave a speech on the Senate floor in which he said: "Trump and I, we've had a hell of a journey. I hate it to end this way.

"All I can say is a count me out. Enough is enough."

But he later became one of his staunchest backers. He voted against convicting Trump in the 2021 impeachment trial, and supported Trump in the 2024 election.

He told the BBC in 2023: "There is a dark side to Donald Trump... and he was a very good president. But I am sticking with him because I saw what he did." He cited Trump's record on the US southern border, the killing of Iran's powerful military commander Qasem Soleimani and the appointment of conservative judges.

Graham was known for his interventionist stance in foreign policy, with his website stating that Graham "consistently pushed for outcomes in the War on Terror that protect our long-term national security interests".

He voted in favour of military action against Iraq in the wake of the September 11 attacks in 2001 and was opposed to the withdrawal of US troops from Afghanistan in 2021, describing it as a "sad and dangerous event for US national security".

"Jihadists all over the world are celebrating," he added. "America will be seen as weak."

Graham was a staunch supporter of Israel.

Israel's Prime Minister Benjamin Netanyahu paid tribute to Graham on Sunday, saying "Lindsey understood that the security of Israel and America are inseparable".

Israel lost "one of its greatest friends", he added.

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