They charm pre-frosh in Sanders Theater and captivate patrons of Upstairs at the Pudding. But the Krokodiloes, Harvard's oldest a cappella group, have found an audience that is less than thrilled to see them.

The Kroks--currently in the middle of their annual world tour--cancelled shows in Shanghai and Beijing after the Chinese government revoked their performance permits in the wake of strained relations with the U.S.

"We were scheduled to give two large performances in Shanghai, the proceeds from which were going to finance part of our tour," Krokodiloes Tour Manager Thomas W. Chalberg '99 wrote in an email message. "In Beijing we were supposed to sing in exchange for our accommodations at the Shangri-La Hotel."

The Kroks received the necessary permits to perform in China from the Chinese Ministry of Culture earlier this year, but the government changed its mind after their relations with the U.S. soured this spring.

"When NATO forces bombed the Chinese Embassy in Belgrade, our permits were re-called for consideration," Chalberg wrote.

And the day after the U.S. government released the Cox Report, which details Chinese espionage in America, the singers' permits were formally revoked.

Ezra F. Vogel, director of the Fairbank center for East Asian studies, said he was not surprised with China's actions.

"I think what happened was with the bombing of the embassy there was a lot of genuine anger all over China," Vogel said, adding that Chinese officials were probably wary of introducing any kind of cultural exchange into such a volatile environment.

He said the release of the Cox Report also contributed to the enormous strain on China-U.S. relations.

"It was an extraordinary event in that it came on top of a lot of huge frustrations in China," he said. "I think the government response in China is quite restrained considering the anger of the people."

According to Chalberg, the Chinese Ministry of Culture said they withdrew the permits because they were not supporting U.S. "cultural activities" in China. This action officially ended all hopes of an official appearance in China.

"If you perform with out a permit, you can be put in jail," he said.

Banned from selling tickets and performing, the Kroks were forced to cancel their shows in China and instead traveled the country on tourist visas.

"We ended up singing for a couple people informally, but even that could have gotten us in trouble, so we were careful," Chalberg said.

Despite their troubles in the Far East, Chalberg said the Kroks are looking forward to upcoming shows in Paris, Tel Aviv and Johannesburg.

"I think [the tour] will be just fine," Chalberg said. "But it's inherently a risky thing, to bring a group around the world.