Lindsey Graham died from aortic dissection, preliminary medical examiner finds

US Senator Lindsey Graham likely died from an aortic dissection linked to hardened arteries, according to a preliminary finding by the medical examiner shared by his office.

The preliminary report found that Graham suffered a tear in the inner wall of the aorta. Officials said the injury was related to the hardening of his arteries.

His office said a final cause of death will be released after toxicological and microscopic testing is completed.

The South Carolina Republican died on Saturday at the age of 71, two days after his birthday. His office had initially said he suffered a "brief and sudden illness."

US President Donald Trump paid tribute to one of his closest allies in Congress, saying Graham was "like a member of the family. It’s very tough."

Trump also said on NBC's Meet the Press that Graham had called him after returning from a visit to Ukraine and "sounded a little bit tired, but perfect."

According to the Associated Press, Trump has ordered flags across the United States to fly at half-staff until next Saturday evening.

Graham served in Congress for more than 30 years and was widely regarded as a leading voice on foreign policy.

He recently worked with the Trump administration on proposed sanctions against Russia and chaired the Senate Budget Committee during Trump's second term.

Under South Carolina law, Governor Henry McMaster will appoint a temporary replacement until voters elect a successor.