The death of Robin Williams has led to an outpouring of grief among fellow actors, fans, and politicians, with US President Barack Obama calling him "one of a kind".

Police found the comedian dead in the bedroom of his home near San Francisco with a belt around his neck on Tuesday, with a coroner later ruling that head died of asphyxia caused by hanging.

Investigators did not say whether a suicide note was found, but did disclose that a pocket knife with signs of dried blood on its blade was being examined, the AFP news agency reported.

The entertainer's body was found by his personal assistant, who entered his bedroom after Williams failed to respond to knocks on his door.

The father of three, had spoken openly of his past struggle with alcohol and substance abuse, and often made self-deprecating references to his addictions in his stand-up routines.

Williams won an Academy Award for Best Supporting Actor for his role in Good Will Hunting, and was known for his eccentric performances in movies including, Flubber, Good Morning Vietnam, and Jumanji.

Below, are some of the responses to his passing:


US President Barack Obama


"[Williams] arrived in our lives as an alien, but he ended up touching every element of the human spirit..the Obama family offers our condolences to Robin's family, his friends, and everyone who found their voice and their verse thanks to Robin Williams.'' 


Comedian, Steve Martin


"I could not be more stunned by the loss of Robin Williams, mensch, great talent, acting partner, genuine soul."


Actor, Kevin Spacey


"Robin Williams made the world laugh & think. I will remember & honor that. A great man, artist and friend. I will miss him beyond measure."


Comedian, Ben Stiller


"I met him when I was 13 and a huge fan and he was so kind...I watched him be kind to every fan i ever saw him with."


Comedian, Russell Peters


"Very sad to hear the news about Robin Williams. Big loss for not just the entertainment world but for the whole world."


Actor, Abishek Bachchan


"Oh captain, my... terrible news about the passing of one of my favourite actors. Mr. Robin Williams. This is the first time he made anyone cry."


Actress, Shabana Azmi


"Robin Williams. What a loss! You leave behind a vaccum difficult to fill but your remarkable body of work will continue to inspire. RIP."


Former boxer, Muhammad Ali


"We were shocked and sorry to hear of Robin's passing. He was a wonderful and loving human being who was always willing and ready to help others. Our prayers and sympathy go out to his family. May he rest in peace."

Source: Al Jazeera and agencies