WASHINGTON, United States (AFP) — Prominent US Senator Lindsey Graham, a key ally of President Donald Trump, died aged 71 following a “brief and sudden illness,” his office said on Sunday.

Graham, known for his foreign policy work, was a staunch supporter of the Iran war and in recent years urged both Trump and the Biden administrations to back Kyiv’s fight against Russia’s invasion.

The Republican senator from South Carolina’s office said in a statement on his official X account that he “passed away from a brief and sudden illness” on Saturday evening. Graham turned 71 on Thursday.

“Senator Graham’s family appreciates prayers at this time and asks for privacy during this incredibly difficult period,” the statement said.

NBC News reported that emergency services responded to a call for “cardiac arrest” at Graham’s Capitol Hill home on Saturday night, according to police scanner audio obtained by NBC and other outlets.

Trump paid tribute to the influential senator on Sunday, calling him “one of the greatest people” in a post on his Truth Social site.

“Senator Lindsey Graham, one of the greatest people and Senators I have ever known, is dead! He was always working, and was a true American Patriot. Lindsey will be greatly missed!!!”

Graham made a failed bid for the presidency in 2016, warning at the time that Republicans should not back Trump because he was a “race-baiting, xenophobic, religious bigot.”

Their relationship was then strained by the January 6, 2021, Capitol insurrection, with Graham saying his Republican colleagues should “count me out, enough is enough” — although he later voted against convicting Trump in his impeachment trial.

Graham reconciled their relationship after Trump returned to office and supported his re-election bid.

– ‘A great friend of Israel’ –

Graham was also a strong supporter of Israel and a hawkish backer of the Iran war.

Israeli Prime Minister Benjamin Netanyahu said: “Lindsey is a great friend of Israel and a cherished friend of mine.”

“Lindsey understood that the security of Israel and America are inseparable. He devoted his life to defending America, strengthening our alliance and standing up for the free world,” Netanyahu said in a statement released by his office.

Israeli President Isaac Herzog said the news left him “shocked and heartbroken.”

“Senator Graham was a beacon of moral clarity and a true leader of the U.S.-Israel partnership,” he said in a post on X.

Ukrainian President Volodymyr Zelensky also said he was deeply saddened by the death of Graham, whom he met in Kyiv as recently as Friday.

“He visited Ukraine ten times during the years of Russia’s full-scale invasion and was here with our people when it was most needed… America and the world have lost a determined leader,” Zelensky said in a Facebook post.

European Commission President Ursula von der Leyen applauded Graham’s fight to support Ukraine, calling him a “determined and fearless leader”.

– ‘Irreplaceable’ –

Graham’s death comes as the weeks-long hospitalization of former Republican Senate leader Mitch McConnell rattles the party over the final months of his long congressional career.

Republicans hold a narrow 53-47 majority in the Senate, but will have little room for missing votes or defections. McConnell was admitted to hospital last month and has not voted since June 11.

Graham was first elected to the US House of Representatives in 1994, before being elected to the Senate in 2002.

He was later re-elected to the Senate in 2008, 2014 and 2020 and most recently served as chairman of the Senate Budget Committee.

South Carolina Governor Henry McMaster described Graham as “irreplaceable.”

“The fiercest of fighters for South Carolina and America — and a loyal and steadfast friend,” McMaster said on X.

Raised in the town of Central, South Carolina, where his parents ran a restaurant and pool hall, Graham was the first in his family to go to college, according to his biography on the Senate website.

He served as a military lawyer and attained the rank of Air Force colonel, an experience that informed his interventionist stance in foreign policy.

In 2002, he voted in favour of military action against Iraq in the wake of the September 11 attacks, and later supported a long-term US presence in Afghanistan.

Graham was a frequent critic of President Barack Obama’s foreign policy, calling him a “weak opponent of evil” in 2015 over his negotiation of a nuclear deal with Iran.