Steve McQueen (C), director and producer of "12 Years a Slave" celebrates with Lupita Nyong'o (L) and the rest of the cast after winning the Oscar for best picture at the 86th Academy Awards in Hollywood, California on March 2. Photo: Reuters
Historical drama 12 Years a Slave has won best picture at the 86th Academy Awards, while space drama Gravity won the lion's share of awards.
Gravity's Alfonso Cuaron became the first Latino to win the best director award, adding to the film's six Oscars for technical achievement.
Cate Blanchett was named best actress for her portrayal of the heroine in Woody Allen's Blue Jasmine.
Matthew McConaughey won the best actor Oscar for Dallas Buyers Club.
It is the second consecutive year the best director and best picture prize have been awarded to different films.
Cuaron praised the "transformative" power of film and singled out the film's star Sandra Bullock as "the soul, the heart of Gravity".
The film - which took five years to complete, and owes much to the technical prowess of British visual effects specialists - also won Oscars for film editing, sound mixing, sound editing, cinematography, visual effects and original score.
Steve McQueen, the British director of 12 Years a Slave, dedicated the best picture Oscar to "all those people who have endured slavery".
"Everyone deserves not just to survive, but to live," he said. "This is the most important legacy of Solomon Northup."
Based on a true story, it follows the life of a free black man - Northup - who is kidnapped and sold into slavery in Louisiana.
Producer Brad Pitt praised "the indomitable McQueen" - a Turner Prize winning artist-turned-director - for "bringing them all together" to tell Northup's story.
Photo taken from BBC
Newcomer Lupita Nyong'o won the best supporting actress award for her film debut as slave worker Patsey.
The Kenyan actress paid tribute to her character and thanked her for her "guidance": "So much joy in my life is thanks to so much pain in someone else's," said the star, who turned 31 this weekend.
The film won a third Oscar for John Ridley's adapted screenplay. "All the praise goes to Northup," Ridley said, "these are his words".
Spike Jonze collected the best original screenplay for Her. Jonze's first film as sole writer and director stars Joaquin Phoenix as a man who falls in love with a computer operating system, voiced by Scarlett Johansson.
As predicted, McConaughey took the best actor prize for his role as real life rodeo cowboy Ron Woodroof, who smuggled HIV drugs into the US.
Cuaron won two Oscars, for direction and film editing. He co-wrote the screenplay with his son Jonas.
The 44-year-old actor, formerly a rom-com regular whose roles centred on his good looks, lost 50lbs (23kg) to play Woodroof in the low budget indie drama.
During his speech, he thanked God "because that's who I look up to".
"He's graced my life with opportunities that I know are not of my hand or any other human hand," he added.
Best actress winner Blanchett paid tribute to her rivals, including Dame Judi Dench - who was not at the ceremony - acknowledging "the random and subjective" nature of awards ceremonies.
McConaughey's co-star Jared Leto won the first Oscar of the night, picking up best supporting actor for his role as transgender woman who becomes Woodruff's business partner and unlikely friend.
(L-R) Best actor winner Matthew McConaughey, best actress winner Cate Blanchett, best supporting actress winner Lupita Nyong'o and best supporting actor winner Jared Leto pose with their Oscars at the 86th Academy Awards in Hollywood, California on March 2. Photo: Reuters
In an emotional speech Leto thanked his mother, who accompanied him to the awards, "for teaching me to dream" and dedicated his award to "those who have ever felt injustice because of who they are, or who you love".
"This is for the 36 million people out there who have lost the battle to Aids," said the 30 Seconds to Mars frontman, whose last film was six years ago.
Dallas Buyers Club also picked up a third award for make-up and hairstyling - with the transformation of Leto and his co-star, Matthew McConaughey, rumoured to have been achieved on a budget of $250 (£150).
Frozen, which recently tipped $1bn (£600m) at the global box office, scored two Oscars.
The 3D film about an icy princess and her sister was named best animated feature film, with its song, Let It Go - performed by star Idina Menzel - winning best original song. It is loosely based on The Snow Queen by Hans Christian Andersen.
The Great Gatsby also picked up two Oscars, for costume design and production design. The awards were picked up by Baz Luhrmann's partner Catherine Martin.
But there were no awards for David O Russell's American Hustle, which had 10 nominations, including nods in all the acting categories. Nor were there any awards for Martin Scorsese's The Wolf of Wall Street.
The first British win of the night came for Tim Webber and his team from London-based company Framestore for their visual effects work on Gravity.
Webber paid tribute to his team, Gravity actors George Clooney and Bullock and director Cuaron "for having the vision to create this breath-taking film and the audacity to make it happen".
The second British win of the night went to director Malcolm Clarke, who won an Oscar for his documentary short The Lady in Number Six: Music Saved My Life.
The film follows Alice Herz-Sommer, the oldest known survivor of the Nazi Holocaust and an accomplished pianist. Paying tribute to Herz-Sommer, who died last week at the age of 110, he praised "her extraordinary capacity for joy and amazing capacity for forgiveness".
"She taught everyone on my crew to be a little bit more optimistic," he added, dedicating his award to her.
Ellen DeGeneres hosted the ceremony, for the second time, at the Dolby Theatre in Hollywood.
The 86th Academy Awards are airing live on ABC from the Dolby Theatre in Los Angeles, with Ellen DeGeneres as host.