Image copyright Sotheby's Image caption An Andy Warhol's portrait of Chairman Mao has sold in Hong Kong

An Andy Warhol portrait of Chairman Mao has been sold at a historic auction in Hong Kong - but fell short of its top estimate of $15m (£12m; HK$116m).

The iconic silkscreen portrait fetched $11m in the sale at Sotheby's on Sunday, or $12.6m after tax and fees.

It was bought by an unnamed Asian collector.

In the past, Chinese officials had stopped versions of the painting being exhibited on the mainland, where censors closely guard Mao's depiction.

Just four years ago, during the first comprehensive survey of Warhol's art in China, the Mao portraits were nowhere to be seen.

Image caption The portrait was based on this photo from Mao's Little Red Book

The portraits, based on a photo in Mao's Little Red Book, are among the most famous images of the 20th Century.

The images immortalised the founder of China's Communist Party as a Pop Art commodity, in the vein of Warhol's Marilyn Monroe and Campbell's Soup Cans.

Warhol began the Mao series in 1972 when ties between then Cold War foes China and the US began to thaw after the historic trip to Beijing by US President Richard Nixon.

Image copyright AFP Image caption The series is in a similar style to his Marilyn Monroe pieces

Chairman Mao was a political leader both deeply revered and feared, and certainly an unlikely subject for the bold colour contrasts of the Pop Art movement.

This particular Mao portrait was sold in 2014 in London for £7.6m ($9.4m) to an also unnamed buyer.