The sudden death of influential Republican Sen. Lindsey Graham of South Carolina will have implications for legislative business in the Senate - where Republicans' slim margin is already under stress with the absence of Sen. Mitch McConnell after he was hospitalised- and the November election.

U.S. Sen. Lindsey Graham died Saturday evening after a "brief and sudden illness.

U.S. Senator Lindsey Graham died Saturday after a brief and unexpected illness, his office said in statement posted on social media.