Starring Anna Diop and Michelle Monaghan, Nikyatu Jusu's debut feature portrays the sacrifices Senegalese nanny Aisha makes to leave her home country and young son behind in order to build a new life.

"In America in particular, we haven't seen enough films that truly reflect the disproportionate level of Black and brown women... domestic workers that keep this country afloat," Jusu told a virtual panel at the festival.

"I wanted to center women who typically are on the periphery of other women's stories," said Jusu, a first-generation American whose family is from Sierra Leone.

Diop, the film's star who is also known for television series "Titans," was born in Senegal and moved to the United States as a child.

The movie, which taps into the horror genre and African folklore as well as issues of race and motherhood, does not yet have a release date.

Sundance, which celebrates independent cinema, was forced to go virtual for a second year running by the surge in Covid-19 cases across the United States driven by the Omicron variant.

The Robert Redford-founded festival usually takes place in the mountains of the western US state of Utah.

The festival's documentary prize went to "The Exiles," in which filmmaker Christine Choy tracks down three exiled dissidents from China's 1989 Tiananmen Square crackdown.

The separate audience prize for best drama went to "Cha Cha Real Smooth," starring Dakota Johnson as an older, engaged woman who strikes up a flirtatious relationship with a directionless recent graduate -- played by writer-director Cooper Raiff.

The film was bought by Apple TV+ during the festival for a reported $15 million -- the largest deal so far at this year's event.

And "Navalny," a secretive new fly-on-the-wall documentary about top Kremlin critic Alexei Navalny, which was added to the festival line-up at the last minute, won the audience documentary prize.

Director Daniel Roher said he wanted the film to spark "global outrage and outcry" over Navalny's imprisonment.

The film, which airs on CNN and HBO Max later this year, follows the Russian opposition leader -- as well as his family and aides -- during the five months he spent in Germany recovering from poisoning in late 2020 and early 2021.

"I want every single human being on the planet Earth to know the name Alexei Navalny," said Roher.

"I want that name to be associated with a grotesque injustice being perpetrated by the Russian state against a man who survived a murder attempt and then was arrested for merely surviving."

Sundance runs until Sunday.