A man who walked into a San Francisco art gallery, grabbed a valuable pencil drawing by Pablo Picasso off the wall, then fled in a waiting taxi.

The drawing, worth hundreds of thousands of pounds, was taken from the Weinstein Gallery near Union Square.

The gallery said Picasso created the one-of-a-kind drawing, Tete de Femme, in 1965.

Officer Albie Esparza told the San Francisco Chronicle that police hoped a member of the public might recognise the piece if someone attempted to sell it.

Other artists whose works are still on display at the gallery include Marc Chagall, Salvador Dali and Joan Miro.

Police described the suspect as a man in his 30s wearing loafers and dark glasses.