Peking University (PKU) cancelled the post-performance discussion after a play based on a historic US First Amendment litigation debuted on its campus.

Top Secret: The Battle for the Pentagon Papers, produced by L.A. Theatre Works, California, US, dramatized the epoch-making moments in 1971 when the Washington Post flouted the Nixon administration and published materials from US government documents about the Vietnam War.

The play's Beijing premiere came to an anticlimactic end without the scheduled Q&A at the Peking University Hall on Friday, when the university suddenly called it off, according to the play's China tour manager, Alison Friedman.

"I hadn't been told [of the cancellation] until during the intermission," Friedman said. "Lu Ying, from PKU, said to me 'We have to cancel it. We are not doing it.'"

Lu, a staffer at Peking University Hall's public relations office, would not say why, she said.

During the second act, Friedman received a text message from Zhu Jing, a project manager of China Arts & Entertainment Group (CAEG), the Chinese company that secured government permission for the show in Beijing, telling her "The university wants the discussion cancelled to avoid any unforeseen consequences," according to Friedman.

Zhu refused to comment Saturday when reached by the Global Times, saying it was the university's decision.

Lu denied the cancellation in a telephone interview with the Global Times, saying the contract the hall had signed with CAEG had said nothing about holding a discussion.

"I think that's an excuse, not a valid reason," said Friedman, "It would've only been an informal discussion of 15 to 20 minutes."

The theater performed from November 21 through 27 in Shanghai and held discussions after every show without any special clearance, she said.

But when they  play was performed at Guangzhou's Sun Yat-sen University, Guangdong Province, on November 29, the host also cancelled the discussion.

"I guess Chinese universities are still very sensitive and close-minded," Friedman said.

The cancellation came as an ironic counterpoint to the play, said PKU economics student Bi Ran, who was in the audience.

The play was performed twice more in Beijing at Tianqiao Acrobatic Theater, Xicheng district over the weekend. A discussion was had on Saturday.

"It was interesting. People talked about Wikileaks and the Internet," Friedman said. "We'll also broadcast the play as part of a deal on Beijing Radio 774 next year," she said.

Xuyang Jingjing contributed to this story.