A Chinese government agency halted its approval process for hit online game World of Warcraft to operate in the country on Monday, deepening its struggle with another agency for power over China's online game sector.

China's publishing regulator returned an application by NetEase, the game's local operator, for approval to operate the game with its first expansion pack, "The Burning Crusade," the agency said in a statement on its Web site. That version of the game was previously operated in China by another partner of Blizzard Entertainment, the game's creator. But China requires new operators of foreign-made online games to submit them for approval and content screening even if the games have been through the process before.

NetEase, which also operates a major local portal, began operating World of Warcraft in September without approval from the publishing regulator, the General Administration of Press and Publication (GAPP), the agency said. The agency ordered NetEase to stop collecting game fees from players and allowing new players to sign up for accounts.

NetEase did get approval from China's cultural ministry to launch the game. But companies in the past have always received approval from GAPP before launching online games, said Eric Wen, managing director at Mainfirst Securities Hong Kong.

"What NetEase has done is something that nobody has done before," said Wen. "The game is still running and, according to NetEase, it has not done anything illegal."

GAPP wants to shut the game down, but whether it will be able to do so is unclear, Wen said.

GAPP last month promised to clean up "unhealthy" content like violence and pornography in China's online gaming sector. State media have amplified concern among many Chinese that online games like World of Warcraft are causing young players to become addicted to the Internet.

A second expansion for World of Warcraft, "Wrath of the Lich King," launched last year but has not been approved for release in China. China could fall even farther behind as Blizzard is also working on a third expansion.

Past changes made to the game to appease Chinese regulators have included dressing skeletons up in flesh to appear as human bodies.

NetEase did not immediately reply to a request for comment. A Blizzard spokeswoman declined to comment.