BREAKING: US Senator Lindsey Graham dies at 71

United States Republican Senator Lindsey Graham of South Carolina has died at the age of 71. His office announced his death on Saturday.

"On the evening of Saturday, July 11, US Senator Lindsey Graham passed away from a brief and sudden illness," Graham's office said in a statement. "Senator Graham's family appreciates prayers during this incredibly difficult time."

Emergency responders arrived at his Capitol Hill home on Saturday night to respond to reports of a "cardiac arrest," according to NBC News. His cause of death has not yet been publicly shared.

Graham had just returned home from a trip to Kyiv, Ukraine, when he fell ill. On Friday, he met with Ukrainian President Volodymyr Zelenskyy to discuss proposed US sanctions on Russia.

During an interview with NBC's "Meet the Press," President Donald Trump said that he had a phone call with Graham hours before Graham was pronounced dead, and that the senator did not mention feeling ill.

"So what makes it even stranger is that I got a call last night sometime. You know, the early evening, maybe in the sevens. And he called and he said, we're all set for the Save America Act. He was pushing the Save America act like crazy. He got back, said he just landed from Ukraine and said, that's a long trip to make. And he said - he sounded a little tired, but perfect, but a little bit tired. Had a right to be when he was a worker. He was really a worker," Trump said.

"But he sounded great, actually... He said he was tired, but he wanted to pass the Save America Act. And I said, well, we're going to get it done, Lindsey. We're going to get it done. I'll see you like soon," Trump recalled. 

Graham served in the US Senate for 23 years, holding his seat since 2003, and was seeking another six-year term in November. He had just celebrated his 71st birthday on July 9, a few days prior to his death.

The longtime senator was a staunch ally to President Trump, who considered Graham a close companion and "wonderful friend."

Graham was never married and had no children. He dedicated his life to public service.

Graham was remembered by his colleagues for his "enthusiasm for life."

"My heart is heavy upon learning of the passing of my friend and colleague," said Republican Sen. Mike Lee of Utah.

"I loved serving with Lindsey and will miss his infectious laugh, quick wit, and enthusiasm for life," he added.

Graham is survived by his sister, Darline Graham, and his nieces and nephews.

South Carolina Governor Henry McMaster will now be responsible for appointing an interim replacement to fill Graham's seat until a special election is held in August. Trump said that he already had an individual in mind to replace Graham.

“I have somebody that I think would be great, but I don’t want to say it now because it’s just too soon with Lindsey,” Trump told NBC. “I don’t even want to talk about anybody, but I do have somebody who I think is really good.”

“They’ll have some people joining," Trump said of the special election. "Some are good, some are bad. But I have somebody that I like, but I’m not going to tell you who now because it’s too soon.”