Conservative US Supreme Court Justice Antonin Scalia has died, setting up a major political showdown between US President Barack Obama and the Republican-controlled Senate over who will replace him just months before a presidential election.
"On behalf of the court and retired justices, I am saddened to report that our colleague Justice Antonin Scalia has passed away," Chief Justice John Roberts said in a statement on Saturday (local time).
Scalia's death at the age of 79 was first reported by the San Antonio News-Express, who said he had apparently died of natural causes while visiting a luxury resort in West Texas.
Appointed to the top US court in 1986 by President Ronald Reagan, Scalia was known for his strident conservative views and theatrical flair in the courtroom.
Obama will face a stiff battle to win confirmation of a nominee to replace Scalia, with Republicans likely to delay in the hope that one of their own wins the November election.
But if Obama does successfully nominate a replacement before his term ends in January, it could tilt the court to the left for the first time in decades.
"Justice Scalia was an American hero. We owe it to him, and the nation, for the Senate to ensure that the next president names his replacement," Senator Ted Cruz of Texas, a Republican presidential candidate, said on Twitter.
The nation's highest court is set to decide its first major abortion case in nearly 10 years as well as key cases on voting rights, affirmative action and immigration.