Another North Korean migrant has managed to sneak into the South Korean Consulate in Beijing. The incident is sure to heat up a diplomatic wrangle between Beijing and Seoul over the fate of 19 North Koreans in the embassy compound.

South Korean officials would not say how the young North Korean woman got past uniformed security guards at the gate of the walled compound in Beijing, which is surrounded by barbed wire fences. But by mid-day she was inside, being questioned by South Korean officials.

Security guards in light blue uniforms could be seen closely examining papers of people seeking visas to go to South Korea. But there was little sign of the regular Chinese police, who wear green or dark blue uniforms.

In the past three weeks nearly 20 North Koreans have sought asylum in the South Korean Consulate, causing a diplomatic standoff between Seoul and Beijing.

In the most contentious incident last week, Chinese security guards rushed into South Korea's diplomatic offices pursuing two North Koreans. They managed to seize one man and drag him away, but had to kick and punch South Korean diplomats to get him out of the compound.

South Korea filed an official protest calling it a violation of treaties protecting the sovereignty of diplomatic offices. But Beijing continues to insist that foreign embassies have no right to grant asylum to people from third countries.

Since March, China has allowed 38 North Korean asylum seekers to leave foreign diplomatic offices in China for South Korea via a third country. But China has taken a tougher stand since the North Koreans began taking refuge in South Korea's Embassy. There is no indication that talks between Seoul and Beijing are close to resolving the problem.

China finds itself in a difficult position. There are tens of thousands of North Koreans hiding in China, fleeing famine and persecution. China considers the North Koreans illegal economic migrants and has a treaty obligation with ally, Pyongyang, to send them back.

But the recent defections to foreign embassies and consulates has put increasing diplomatic pressure on China to change its policy.

Chinese officials are concerned it will encourage more defections if they continue to allow North Koreans to have safe passage out of China.