William Friedkin, the groundbreaking US director of "The Exorcist" and "The French Connection," died on Monday, a family friend told AFP. He was 87.

Friedkin passed away in Los Angeles after suffering unspecified health issues in recent years, said Stephen Galloway, a former Hollywood Reporter executive editor.

"He died this morning," confirmed Galloway, after speaking with Friedkin's wife.

The director had "been working until a few weeks ago," but "had been in declining health," he added.

Oscar-winning director Guillermo del Toro led the tributes on Monday, calling Friedkin "one of the Gods of Cinema."

"Cinema has lost a true Scholar and I have lost a dear, loyal and true friend," he wrote on social media.

Fellow horror director Eli Roth posted a tribute on Instagram to "one of the most impactful directors of all time" who "set the course of my life in a different direction."

Actor Elijah Wood described Friedkin as "a true cinematic master whose influence will continue to extend forever."

Friedkin was among a crop of influential young "New Hollywood" directors in the 1970s who fundamentally reshaped the US film industry, upsetting a long-established system in which powerful studio producers had reigned supreme.

Alongside fellow auteurs such as Francis Ford Coppola and Martin Scorsese, Friedkin exploded onto the Hollywood scene in 1971 with the gritty cop drama "The French Connection."

It won five Oscars, including for best director and best picture.

Friedkin followed that up with "The Exorcist," in 1973. It was a huge commercial and critical hit, as well as being deeply controversial.

The shocking film about a 12-year-old girl possessed by the devil was nominated for 10 Oscars, winning two, and grossed an eventual $440 million.

The movie has spawned multiple sequels, including an upcoming trilogy from horror producer Jason Blum in which Ellen Burstyn returns as the original film's heroine.

In a statement Monday, Blum said he was "personally indebted" to Friedkin.

"More than any other filmmaker, he changed both the way directors approached horror films and also the perception of horror films in the broader culture," he said in a statement obtained by trade website Deadline.

"We are deeply saddened to hear of his passing and intensely grateful for the body of work he has left behind."

Following the stratospheric success of "The Exorcist," Friedkin's career went into sharp decline.

He released "Sorcerer" in 1977 -- a hugely expensive flop in its time, although fans such as bestselling horror author Stephen King praised the film in tributes Monday.

"Very sorry to hear of the passing of William Friedkin, a deeply talented filmmaker," King wrote. "THE EXORCIST is great, but for me the real classic was SORCERER."

Friedkin continued directing well into his 80s.

His final film, "The Caine Mutiny Court-Martial," starring Kiefer Sutherland, is set to premiere at this year's Venice Film Festival.

"Working with William Friedkin was one of the great honors of my career," Sutherland said in a statement. "My condolences go to Sherry and his family."

Friedkin, who was once married to French actress Jeanne Moreau, is survived by his fourth wife, Sherry Lansing -- a former Paramount Pictures studio chief -- and two sons.