WATCH: Live Coverage of Death of Supreme Court Justice Antonin Scalia

U.S. Supreme Court Justice Antonin Scalia, a leading conservative voice on the high court, has died at the age of 79, a government source and a family friend told CNN on Saturday.

Scalia died in his sleep during a visit to Texas.

A government official said Scalia went to bed Friday night and told friends he wasn’t feeling well. Saturday morning, he didn’t get up for breakfast. And the group he was with for a hunting trip left without him.

Someone at the ranch went in to check on him and found him unresponsive.

The U.S. Marshals Service is not investigating Scalia’s death, an official told CNN. They are helping to arrange for his body to be returned.

They were present because marshals sometimes help supplement security for traveling justices.

In a statement, Chief Justice John Roberts said he and other justices were “saddened” to hear of Scalia’s passing.

“He was an extraordinary individual and jurist, admired and treasured by his colleagues,” Roberts said. “His passing is a great loss to the court and the country he so loyally served. We extend our deepest condolences to his wife Maureen and his family.”

Deputy White House Press Secretary Eric Schultz said President Barack Obama was informed of Scalia’s passing on Saturday afternoon.

“The President and First Lady extend their deepest condolences to Justice Scalia’s family. We’ll have additional reaction from the President later today,” Schultz said.

Scalia’s death in an election year sets up a titanic confirmation tussle over his successor on the bench. The already challenging task of getting a Democratic president’s nominee through a Republican-controlled Senate will made even more difficult as the fight over Scalia’s replacement will emerge as a dominant theme of an already wild presidential election.

“His departure leaves a huge political fight in the offing because this is a court with five Republican appointees (and) four Democratic appointees,” CNN Senior Legal Analyst Jeffrey Toobin said.

Major presence on high court

Appointed to the court in 1986 by President Ronald Reagan, Scalia was a conservative icon who transformed the court by instilling in it his belief that judges should follow the precise words of the Constitution and not apply a modern interpretation.

He was the first justice of Italian-American heritage and passed through confirmation with a unanimous vote.

Scalia changed oral arguments as he became an active participant with tough questions for advocates.

He will be best known, perhaps, for his landmark decision District of Columbia v. Heller, holding that the Second Amendment protects the right to posses a firearm at home. He was a critic of Roe v. Wade and dissented in last term’s same-sex marriage cases.

Conservative in thought, not in personality

The jaunty jurist was able to light up, or ignite, a room with his often brash demeanor and wicked sense of humor, grounded always in a profound respect for American law and its constitutional traditions.

“What can I say,” was a favorite phrase of the man colleagues knew as “Nino.” As it turned out, quite a lot.