Clint Eastwood's Letters from Iwo Jima was named best film of 2006 by the U.S. National Board of Review of Motion Pictures Wednesday, capturing the first major prize of the Oscar season.

"This is his masterpiece," NBR president Annie Schulhof said. "I was blown away by its delicacy, the poignancy of how he talks about war. I think it's also a searing condemnation of war. It was a unique view of the Japanese side of the battle. We don't always see that."

Martin Scorsese, still searching for his first Oscar, earned best director from the board for his Boston-set crime saga The Departed.

Helen Mirren was named best actress for her work in The Queen, in which she portrays Queen Elizabeth II as the monarch struggles to deal with the death of Princess Diana.

Forest Whitaker won the best actor award for his role as ruthless Ugandan dictator Idi Amin in The Last King Of Scotland, while Djimon Hounsou nabbed best supporting actor for playing a fisherman caught in South Africa's cutthroat black market jewel trade in Blood Diamond.

Best documentary went to An Inconvenient Truth, featuring former U.S. vice-president Al Gore and his concerns about global warming.

Three Canadians were also honoured.

Toronto's Catherine O'Hara won best supporting actress for her role as an aging movie star in the Christopher Guest comedy For Your Consideration; Ryan Gosling of London, Ont., received the breakthrough performance by an actor prize for playing an inspiring inner-city teacher with a drug problem in Half Nelson; and Montreal's Jason Reitman earned best directorial debut for Thank You for Smoking, a satire centred on a Big Tobacco spokesman's struggle to remain a role model for his young son.

Second Iwo Jima film by Eastwood

Letters from Iwo Jima — which opens in select locations in the U.S. on Dec. 20 — tells the story of the bloody 1945 Battle of Iwo Jima between the U.S. and Imperial Japan from the perspective of Japanese soldiers who fought in it.

The film was originally scheduled for a February 2007 release, but was moved up so as to be eligible for this February's Academy Awards.

A companion film by Eastwood, Flags of Our Fathers, hit theatres in October. It presents Iwo Jima — a key event near the end of the Second World War — from the point of view of American soldiers who famously raised their country's flag during the battle.

Both of Eastwood's Iwo Jima sagas made their way onto the board's Top 10 of 2006 list, which also included, in alphabetical order: Babel, Blood Diamond, The Departed, The Devil Wears Prada, The History Boys, Little Miss Sunshine, Notes on a Scandal and The Painted Veil.

Often an indicator of what to expect at the Oscars, the National Board of Review awards are voted on by 120 film professionals belonging to the century-old league of film historians, students and educators.

Last year the board selected George Clooney's Good Night, And Good Luck as best film, while Ang Lee won best director for Brokeback Mountain. Philip Seymour Hoffman took the best actor prize for playing famed journalist Truman Capote in Capote, and Felicity Huffman was named best actress for her portrayal of a transsexual who discovers her long-lost son, in Transamerica.

Lee went on to win the corresponding Academy Award.