NEW YORK -- Disney announced on Thursday that the coronavirus pandemic had forced it to indefinitely postpone the release of big-budget film "Mulan," while pushing back upcoming installments of "Star Wars" and "Avatar" by a year.

The live-action "Mulan" had already been postponed twice, with its release most recently delayed to August 21.

Following the postponement of "Tenet," a sci-fi thriller that theater operators were counting on to jump-start attendance, it appears the summer film calendar is collapsing.

"Over the last few months, it's become clear that nothing can be set in stone when it comes to how we release films during this global health crisis, and today that means pausing our release plans for 'Mulan' as we assess how we can most effectively bring this film to audiences around the world," a Walt Disney Studios spokesperson said in a statement.

Disney also announced that the release schedule for future installments of the "Star Wars" and "Avatar" sagas has been pushed back by a year.

The "Avatar" sequel will be released in December 2022, and the 10th episode of "Star Wars" in December 2023, rather than in 2021 and 2022 respectively.

The releases will then be staggered, with "Avatar" films in 2024, 2026 and 2028, and "Star Wars" in 2025 and 2027.

"Avatar" director, screenwriter and co-producer James Cameron said on Twitter that the coronavirus had delayed live-action filming in New Zealand, and that special effects work in Los Angeles had yet to restart -- forcing the postponement of the film's release.

Disney had decided in early April to push back a dozen Marvel films, including "Black Widow," starring Scarlett Johansson.

That is now scheduled to come out November 6, forcing all the other films in the franchise to shift back.

Following "Black Widow" -- the next Disney studio film set to hit screens -- comes "Soul," Pixar's new animated feature under the Disney banner, slated for November 20.

Disney has also postponed, to an unspecified date, "The French Dispatch" by director Wes Anderson, which was previously set to debut on October 16.

© Agence France-Presse