Justice Antonin Scalia
Justice Antonin ScaliaReuters

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

Scalia reportedly 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. He did not get up for breakfast on Saturday morning, and the group he was with for a hunting trip left without him.

Someone at the ranch later went in to check on him and found him unresponsive, according to CNN.

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 without applying a modern interpretation.

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

The conservative judge’s death set off an immediate debate about whether President Barack Obama should fill the seat in an election year.

Obama said Saturday night that he plans to nominate a replacement, but Senate Majority Leader Mitch McConnell said the nomination should wait until the next president comes into office.

Top Democrat Harry Reid called for the seat to be filled "right away."

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."

Speaking Saturday while on a presidential trip to Rancho Mirage, California, Obama vowed to nominate a successor to Scalia, who he called "a towering legal figure."

"There will be plenty of time for me to do so and for the Senate to fulfill its responsibility to give that person a fair hearing and a timely vote," Obama said, according to CNN. "These are responsibilities that I take seriously, as should everyone. They're bigger than any one party. They are about our democracy. They're about the institution to which Justice Scalia dedicated his professional life."

Earlier Saturday, McConnell, a Kentucky Republican, called for the vacancy to be filled after Obama's presidency ends.

"The American people‎ should have a voice in the selection of their next Supreme Court Justice. Therefore, this vacancy should not be filled until we have a new president," McConnell said in a statement.

Reid, who represents Nevada, called for the seat to be filled "right away."

"With so many important issues pending before the Supreme Court, the Senate has a responsibility to fill vacancies as soon as possible," Reid said in a statement quoted by CNN. "It would be unprecedented in recent history for the Supreme Court to go a year with a vacant seat. Failing to fill this vacancy would be a shameful abdication of one of the Senate's most essential Constitutional responsibilities."