The United States is expressing deep concern over Thursday's incident in Beijing in which Chinese police entered the South Korean consulate and dragged away a North Korean asylum seeker. U.S. officials say North Koreans in China should not be forcibly returned home.

Thursday's incident in Beijing appears to reflect a toughening of the Chinese approach to North Korean asylum seekers, dozens of whom have fled into foreign missions - including ones from the U.S. - in the capital and other major Chinese cities in recent months.

In most of the previous cases, the North Koreans have subsequently been allowed to leave China for South Korea. But in this latest incident, Chinese police entered the premises of the South Korean consulate and seized a North Korean national. The man was one of two north Koreans who had, moments before, gone inside with one consulate staff member who was reported injured in a scuffle as diplomats attempted to stop the police.

South Korea condemned the seizure of the man as a violation of international law, a statement echoed later at a briefing here by the State Department spokesman Philip Reeker, who said, "We are extremely concerned at reports that Chinese police entered, uninvited, into the premises of the South Korean embassy in Beijing.

"We certainly regard the inviolability of diplomatic and consular premises as the bedrock principle that is essential to the conduct of international relations, and we expect all nations to abide absolutely by their solemn legal obligations regarding such inviolability under the Vienna Conventions."

Mr. Reeker said U.S. officials have "consistently" told the Chinese government that North Koreans should not be returned to face persecution there.

He further said the United States expects China to adhere its obligations under the 1967 U.N. protocol on the status of refugees, to which it is a party, which prohibits the expulsion or return of refugees to countries where their lives and freedom would be threatened.

China contends the North Koreans are not refugees deserving special protection, but rather economic migrants who should be sent home under terms of a treaty it has with Pyongyang.

The Chinese foreign ministry said Thursday foreign diplomatic missions are being told they must hand over to police "illegal intruders," though Mr. Reeker said he was unaware of such a message being received by the U.S. embassy.