Yesim Ustaoglu's coming home drama Pandora's Box has won the Golden Shell for best film at the 56th edition of San Sebastian.

An international premiere at the festival, Ustaoglu's Turkish-French-German-Belgian co-production tells the story of three siblings forced to put their differences aside to find their missing mother.

The film beat off strong competition from the likes of Kristian Levring's Fear Me Not and Spanish director Javier Fesser's Camino, which received favourable reviews and was a world premiere at San Sebastian.

Pandora's Box' lead, Tsilla Chelton, also shared the best actress prize with Melissa Leo, star of Courtney Hunt's drama Frozen River.

Winterbottom's silver shell award for best director was greeted with surprise by some in attendance at the festival following mixed reactions to his film Genova from industry and reviewers alike.

Other key award winners were Samira Makhmalbaf's Two-Legged Horse, which took the special jury prize, Oscar Martinez' best actor prize for his role in Daniel Burman's Argentinian-French-Spanish co-production El Nido Vacio, and Benoit Delepine and Gustave Kervern won best screenplay for their quirky French film Louise-Michel.

Awards in full

Golden shell for best film: Pandora's Box (Yesim Ustaoglu)
Special jury prize: Two-Legged Horse (Samira Makhmalbaf)
Silver shell for best director: Michael Winterbottom (Genova)
Silver shell for best actress: Tsilla Chelton (Pandora's Box) and Courtney Hunt (Frozen River)
Silver shell for best actor: Oscar Martinez (El Nido Vacio)
Jury prize for best screenplay: Benoit Delepine, Gustave Kervern (Louise-Michel)
Jury prize for best cinematography: Hugo Colace (El Nido Vacio)
Altadis new directors award: Cao Baoping for The Equation of Love And Death
Horizontes award: Gasolina (Julio Hernández Cordon)
TCM audience award: Burn After Reading (Joel and Ethan Coen)
European film award: Lemon Tree (Eran Riklis)
Youth award: Amorosa Soledad (Martin Carranza, Victoria Galardi)
FIPRESCI award: Tiro En La Cabeza (Jaime Rosales)