Hollywood stars have called on Russia not to let hunger striking Ukrainian director Oleg Sentsov die in prison.

Actress Naomi Watts, Oscar-winning actor and director Christoph Waltz, together with Guillermo del Toro have urged the Kremlin to release the filmmaker, who has been refusing food in a remote jail in northern Siberia for 118 days.

They and the rest of the jury at the Venice film festival, which ends today, said Mr Sentsov had lost 30kg since he began his protest on 14 May.

The 42-year-old was jailed for 20 years for terrorism and arms trafficking after a trial denounced as "Stalinist" by Amnesty International.

The Venice jury, led by Del Toro - who won two Oscars this year including best film for "The Shape of Water" - said that Mr Sentsov had been "imprisoned and tortured... after a trial that clearly did not respect the rights of the defence."

They urged the Kremlin to release him immediately "so that Oleg is not left to die".

It was the second call to free Mr Sentsov at the festival.

Last week top Russian documentary maker Victor Kossakovsky made an emotional appeal for Mr Sentsov's life.

"We must not forget him. You must write, write, write," he told reporters.

"We have to tell him we remember him."

"The Kremlin releasing him would "not (be) political but a human act", he added.