US artist Ellsworth Kelly dies aged 92
Influential abstract artist Ellsworth Kelly has died at the age of 92.
According to dealer and gallery owner Matthew Marks, he died of natural causes at home in New York.
Known for vibrant works with geometric shapes and bright colours, the artist had retrospectives at New York's Guggenheim and the San Francisco Museum of Modern Art over his career.
In 2013, he was presented with the National Medal of Arts by US President Barack Obama.
Kelly was born in Newburgh, New York, in 1923 and served in the US military during World War Two before studying art at Boston's School of the Museum of Fine Arts. He went on to travel and study in Paris.
On his return to New York, he held his first solo show in 1956.
Influenced by artists such as Picasso and Matisse, Kelly's work was dubbed by art historian Jules Langsner as "hard-edge painting".
His pieces included paintings, sculpture and tattoos.
Analysis by Will Gompertz, arts editor
Ellsworth Kelly was a giant of post-war American painting. He belonged to the pioneering New York-based Abstract Expressionist school that counted Mark Rothko and Clyfford Still among its number.
What made his work stand out (in every respect) was his commitment to working with colour at its greatest intensity, not mixed and applied wet-on-wet as was the preference for many of his peers.
By doing this he became the American artist who arguably bridged the gap between European modernism as practiced by Matisse and Picasso - and Manhattan's bullish expressionism.
He saw the world in fragments of vibrant hues and had the skill and intellect to make sense of the complexities of life in the simplest of shapes and brightest of colours.
He told W magazine in a 2012 interview: "I know how not to go too far or how not to go too small. I'm doing a sculpture now, a rather big one - and it's really waiting and waiting.
"I sometimes don't try to invent something. I wait for some kind of a direction - and it happens. I get an angle, for instance, and it just appears, and I say, 'Oh my God - that's it!'"
Kelly also carried out public commissions around the world, including a memorial for the United States Holocaust Memorial Museum in Washington.
In 2000, alongside architect Richard Rogers and composer Stephen Sondheim, he was presented with a Praemium Imperiale award, one of the world's biggest art prizes.
Kelly is survived by his partner, photographer Jack Shear.