American actor Michael K Williams, best known for starring in HBO drama series The Wire, has been found dead in his New York apartment. He was 54.

US media quote law enforcement sources as saying he died from a suspected drug overdose. This has not been officially confirmed.

Williams - who was nominated for three Emmy Awards - had openly discussed his struggles with drugs over the years.

In The Wire, he played Omar Little, a gay, streetwise robber of drug gangs.

He was also known for playing Albert "Chalky" White, a powerful gangster, in the Prohibition period TV series Boardwalk Empire.

New York Police Department spokesman John Grimpel said police went to Williams's Brooklyn apartment after receiving an emergency call at 14:00 local time on Monday (18:00 GMT).

Fellow actors and filmmakers have been paying tribute on social media.

"The depth of my love for this brother, can only be matched by the depth of my pain learning of his loss," The Wire co-star Wendell Pierce tweeted.

"A immensely talented man with the ability to give voice to the human condition portraying the lives of those whose humanity is seldom elevated until he sings their truth," Pierce added.

"If he was in a scene he was the best thing about it. Period," wrote actor Edward Norton, who worked with Williams on the 2019 film Motherless Brooklyn.

I feel punched in gut to learn we’ve lost Michael K Williams. Soul anguished. Getting to work with him was one of the greatest privileges I’ve had in my career. My admiration for his talent was boundless, like so many. If he was in a scene he was the best thing about it. Period.

— Edward Norton (@EdwardNorton) September 6, 2021

He had a really rare gift for being fully present in the moment & for conveying the layers under the words. He ran so deep. He was also kind & generously enthusiastic. I’ll be forever grateful that he graced ‘Motherless Brooklyn’ & that I got to share space & time w him. RIP💔

— Edward Norton (@EdwardNorton) September 6, 2021

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"This is heartbreaking to learn. We have lost an enormous talent in Michael K Williams," tweeted Star Trek actor George Takei.

Filmmaker James Gunn described Williams as one of the "most gentle souls I've ever met".

"Rest in Peace Michael K Williams. Gone far too soon. A man that taught me so much. Thank you for your wisdom," wrote British actor Damson Idris.

In a statement, HBO TV network, which aired 60 episodes of The Wire between 2002 and 2008, said: "We are devastated to learn of the passing of Michael Kenneth Williams, a member of the HBO family for more than 20 years.

"While the world is aware of his immense talents as an artist, we knew Michael as a dear friend who was beloved by all who had the privilege to work with him. We send our deepest condolences to his family for this immeasurable loss."

Born in New York in 1966, Williams began his career as a dancer and performed with Madonna and George Michael before moving into acting, with companies including the prestigious National Black Theatre Company.

In a BBC interview in 2018, Williams explained why The Wire was such a successful series.

"I think it has just stayed with people because it's still relevant now, because of the climate of what's going on in the United States. I think it's actually a little sad," he said.

"It was the first show I saw that was created as what I call 'edutainment'. It dived so honestly into what was wrong in our society, from the police department to our lawmakers to our school system, and the media. It represented what was happening in our community."

The actor had also publicly admitted his personal struggles with drugs over the years, even when he was starring in The Wire.

"I was playing with fire," he said in an interview with news website NJ.com in 2012.

"It was just a matter of time before I got caught and my business ended up on the cover of a tabloid or I went to jail - or worse," Williams said.