BEIJING — One of China’s most popular directors, Feng Xiaogang, was determined to triumph at the box office with the release of his new film “Youth” during the weeklong National Day holiday.

In the run-up to the film’s expected release later this week, Mr. Feng and his actors had been touring China, promoting the romantic drama set against the Cultural Revolution and China’s brief, harrowing war against Vietnam.

But then Mr. Feng’s premiere was abruptly canceled.

Chinese film buffs say “Youth” appears to have fallen victim to official jitters ahead of a Communist Party congress next month, which is expected to give President Xi Jinping five more years in power. Mr. Feng said on Sunday that the film’s release had been indefinitely postponed, meaning the premiere would not coincide with the holiday, one of the most popular weeks at the country’s cinemas.

“Due to reasons that leave me no choice, the nationwide roadshow for ‘Youth’ can only go this far,” Mr. Feng said at a tearful news conference in Shanghai. “We have to say farewell to everyone before it even started, and I feel helpless.”