By Silvia Aloisi

ROME, Oct 19 (Reuters) Oscar-winning Italian director Giuseppe Tornatore returns to the big screen after a six-year break with his new film ''The Unknown'', the harrowing story of an Ukrainian immigrant haunted by her dark secrets.

Like so many other Eastern European women seeking a better life in Italy, Irena has ended up in a prostitution ring and plunges into a spiral of sexual abuse, exploitation and violence.

When she finally appears to be finding a way out of her misery, she sets her sights on an Italian family of goldsmiths and becomes the trusted maid of their little girl. But her past catches up with her.

''The Unknown'' is a bleak tale of despair and immigrants' alienation that could not be more different from the nostalgic, fable-like movies Tornatore is famed for -- even though his first film in 1985, ''Il Camorrista'', was a Mafia drama.

But the 50-year old Sicilian who won the Academy Award for best foreign film in 1989 with ''Cinema Paradiso'' -- the heart-warming story of a small boy's passion for the silver screen -- said his latest film had no political intent.

''The events described in the movie have a clear resonance with the world in which we live,'' Tornatore told reporters after ''The Unknown'' won warm applause at the Rome film festival.

''But I never thought this film should be a film of denunciation, instead I wanted it to have the undertones of a thriller,'' Tornatore said.

''I did some research on how these immigrant women live, so I was aware of their situation. But I think that kind of engaged cinema doesn't make a lot of sense anymore. If you see something bad, you should go to the police,'' he said.

Italian newspapers gave their thumbs up to ''The Unknown'', Tornatore's first film since ''Malena'' -- in which the sultry Monica Bellucci rocked a sleepy Sicilian town during World War Two -- was met by lukewarm reviews.

''A wonderfully shot film full of coup de theatre which will make the heads of not-so-concentrated spectators spin,'' wrote film critic Natalia Aspesi, highlighting the effective use of rapid flashbacks to convey Irena's anguish throughout the film.

The cast includes several well-known Italian actors, but Tornatore singled out for praise Ksenia Rappoport, a little-known Russian actress, for her portrayal of the lead character.

''My biggest fear was that he'd be disappointed in his expectations,'' Rappoport said in the halting Italian she speaks throughout the film. ''He had not seen any of my previous works so I have no idea how he decided that I would be able to play this role.'' REUTERS PB HT1620