Richard Donner, the filmmaker best known for his effortless mix of action and comedy in the “Lethal Weapon” series, “Superman” and “The Goonies,” died Monday in Los Angeles at age 91, his family said through a Warner Bros. spokesperson. The cause of death was not immediately known.

Steven Spielberg, who was executive producer and has story credit on the 1985 hit “The Goonies,” posted a tribute to Donner, saying, “Dick had such a powerful command of his movies, and was so gifted across so many genres. Being in his circle was akin to hanging out with your favorite coach, smartest professor, fiercest motivator, most endearing friend, staunchest ally, and — of course — the greatest Goonie of all.”

Mel Gibson, star of four “Lethal Weapon” movies, all directed by Donner, as well as the director’s “Conspiracy Theory” and “Maverick,” released a statement Monday: “Donner! My friend, my mentor. Oh, the things I learned from him! He undercut his own talent and greatness with a huge chunk of humility referring to himself as ‘merely a traffic cop.’ He left his ego at the door and required that of others. He was magnanimous of heart and soul, which he liberally gave to all who knew him.”