Director Sebastian Junger accepts the grand jury prize for documentary film for Restrepo at the 2010 Sundance Film Festival awards ceremony on Saturday in Park City, Utah. ((Peter Kramer/Associated Press))

The Ozark Mountains drama Winter's Bone and the war-on-terror documentary Restrepo won top honours Saturday among U.S. movies at the Sundance Film Festival in Park City, Utah.

Director Debra Granik's Winter's Bone, the story of a 17-year-old trying to uncover the fate of her father among the criminal clans of the Ozarks, earned the grand jury prize for American dramas at Sundance, Robert Redford's showcase for independent cinema.

Granik and co-writer Anne Rosellini also won the festival's Waldo Salt screenwriting award for their script, based on the novel by Daniel Woodrell.

The awards came hours after Roadside Attractions bought North American theatrical rights for Winter's Bone. Roadside plans to release the film this summer.

It was the second straight Sundance drama winner featuring a breakout role for a young actress. Jennifer Lawrence, whose credits include Charlize Theron's The Burning Plain, offers a fearless lead performance in Winter's Bone, which follows Gabourey Sidibe's sizzling debut in the title role of Precious: Based on the Novel Push By Sapphire, last year's Sundance dramatic winner.

The grand jury prize for documentary went to Restrepo, which chronicles the lives of an American platoon fighting in Afghanistan, where the troops have erected an outpost to a fallen comrade, Pte. Juan Restrepo. The film was directed by journalist Sebastian Junger, author of The Perfect Storm, and photographer Tim Hetherington.

"We're in the middle of two wars," Junger said. "If our movie can help this country understand how to go forward, we would be incredibly honoured by that."

The audience award for favourite U.S. drama chosen by Sundance fans was given to the romance happythankyoumoreplease, written and directed by and starring Josh Radnor, the star of TV's How I Met Your Mother.

Waiting for Superman — a study of the problems at U.S. public schools that was directed by Davis Guggenheim, who made the Academy Award winner An Inconvenient Truth — earned the audience award for U.S. documentaries.

Canadian nabs acting accolade

A special jury prize was given to Sympathy for Delicious, Mark Ruffalo's directing debut, in which he co-stars with friend and screenwriter Christopher Thornton, who plays a paralyzed DJ with the power to heal others but not himself.

Canadian actress Tatiana Maslany was among the prizewinners. The Newfoundland native won a special jury prize for Breakout Performance in World Cinema playing a sexually rebellious 14-year-old in Adriana Maggs' Grown Up Movie Star.

Director David Michod's Australian teen drama Animal Kingdom earned the dramatic jury prize for world cinema, while the world documentary award went to Danish filmmaker Mads Brugger's The Red Chapel, chronicling a regime-challenging trip to North Korea.

Javier Fuentes-Leon's Peruvian ghost story Undertow won the world-cinema audience honour for dramas, and Lucy Walker's British-Brazilian production Waste Land, about an art project at a massive landfill, received the documentary audience prize for world cinema.