The Obama administration has warned China about the use of undercover operatives in the United States who are assigned to pressure Chinese fugitives to return home and in some cases to recover assets gained through alleged corruption, U.S. officials said.

The warning was delivered in the past several weeks through diplomatic channels. As described by officials, it was a matter of informing China that the United States is aware of the operation, which Chinese media accounts have alluded to, and voicing the administration’s concerns rather than threatening any specific retaliatory action.

The warning was issued in the past several weeks through diplomatic channels, officials said, confirming an account that appeared Sunday evening on the New York Times Web site.

The administration has reminded the Chinese government, with which the United States has no extradition treaty, that any attempt to repatriate alleged fugitives should be conducted through proper U.S. legal channels.

China’s foreign ministry has not yet responded to a faxed request for comment on the issue.

In a commentary published Monday, Xinhua, a state-controlled newswire, called the Times report “astonishing” and “inexplicable” because the U.S. side “promised not only once to strengthen anti-corruption cooperation with China.”

“On one hand, [the U.S.] showed a cooperative attitude, on the other they issued a warning,” it read.

“Chinese people can’t help but wonder if the U.S. is on the side of corrupt officials, or on the side of justice,” the Xinhua commentary said.

The Times reported that young Chinese agents, operating undercover, have been dispatched to a number of countries to induce the alleged fugitives to return to China, sometimes with threats against relatives at home.

In December, the newspaper reported, Australia officially complained to the Beijing government after two Chinese agents arrived in Melbourne, without informing Australian authorities, to apprehend a Chinese national accused of bribery.

Although the Justice Department has charged Chinese government entities with alleged cybertheft from U.S. companies, the administration has been reluctant to publicly challenge China over alleged illegal activity toward U.S. government entities, including a massive breach of U.S. government personnel records earlier this year that many in U.S. intelligence are convinced was a Chinese operation.

Officials have cited factors including concern that proving such allegations would require revealing U.S. intelligence sources and methods.

Emily Rauhala contributed from Beijing.