US Republican senator Lindsey Graham, a key ally of Donald Trump, a staunch Israel supporter, and a foreign policy hawk who advocated for military intervention against Iran, has died from a sudden illness, his office said in the early hours of Sunday.

The US Republican senator died of a sudden illness, his office said. He was 71.

Republican senator had served in the Senate since 2003 and was a sharp critic of Trump before becoming one of his most loyal backers

Mr Graham, 71, a veteran senator, is notorious for often urging the US to go to war, especially wars that favour Israel.