China has detained a Korean-American missionary and questioned dozens of other people accused of helping North Koreans trying to flee China. The detention follows reports that China has rounded up other missionaries and aid workers in an effort to stop the flow of refugees out of North Korea.

A spokesman for the U.S. Embassy in Beijing says China detained an American last week in northeastern China. U.S. officials won't give the man's name, but a news agency identified him as Joseph Choi, and reports he is accused of helping fleeing North Koreans.

Other news accounts say Chinese officials have been cracking down on missionaries in the border region for months and that dozens have been taken into custody.

China's Foreign Ministry won't confirm those reports or say anything about the detained American.

Ministry spokesman Kong Quan insists "China handles all illegal migrants in a 'humanitarian' fashion."

China says all the North Koreans who cross into China are economic migrants who must be shipped home.

But human rights groups say these migrants have a reasonable fear of persecution if they return to North Korea and should be protected as political refugees.

Up to 300,000 North Koreans have crossed the border into China, fleeing hunger and repression at home.

Several dozen North Koreans have managed to get out of China recently by storming into diplomatic buildings in China, demanding asylum and passage to South Korea. Chinese police sparked a diplomatic spat between China and Japan when they went into the Japanese consulate in Shenyang to seize five fleeing North Koreans.

Chinese officials have refused Japanese demands to return the group and say there are no talks under way to resolve the stand-off over the fate of the group. The Foreign Ministry spokesman says China is still confirming the identity and nationality of the people seized by police, but he says they are in "good condition."