The death of a panda at a Japanese zoo has strained diplomatic relations between Beijing and Tokyo.
China has dispatched a team of officials to investigate the death of Xing Xing during a routine procedure last week.
Xing Xing, a 14-year-old male also known as Kou Kou, reportedly died after being anesthetized by zookeepers who were preparing to collect sperm to use in the artificial insemination of his partner, Tan Tan.
The death of the panda, who had been on loan to Oji Zoo in Kobe since 2002, stirred conspiracy theories in China.
Diplomatic relations between China and Japan were already under strain as they hash out the fate of a Chinese fishing boat captain.
The captain's boat collided with two Japanese coast guard ships in disputed waters last week. Japanese authorities claim the captain deliberately struck the vessels. The panda died on Thursday — just two days after the collision.
Citing Shanghai's Oriental Morning Post, Britain's Daily Telegraph newspaper .
Under a 10-year breeding agreement, officials sent Xing Xing from the Wolong Panda Research Center in southwestern China's Sichuan province to replace another male panda, Xinhua reported.
The bear reportedly was scheduled to return to China in July but the China Wildlife Conservation Association extended its agreement with the zoo by five years.
"It is still too early to comment (on the death)," Wolong National Natural Reserve deputy chief Li Desheng told the Singapore-based AsiaOne website. "The experts have yet to ... investigate the case."
China's State Forestry Administration asked Japanese authorities to preserve the panda's corpse for examination, AsiaOne reported.
The Telegraph reported that China leases its pandas to other nations for about $1 million per year.
Pandas often have trouble reproducing in captivity. Attempts to breed Xing Xing and Tan Tan produced a stillborn cub in 2007; the next attempt resulted in a live cub, but it died within days of its birth, the Telegraph reported.
