China said it had Tokyo's consent when it grabbed five people from a Japanese consulate in northern China earlier this week - a claim Tokyo denies.
China's official Xinhua news agency quotes Chinese Foreign Ministry spokesman Kong Quan as saying the Japanese side should keep calm and understand the Chinese move out of goodwill, and not aggravate the issue.
Mr. Kong said Chinese police received consent from the Japanese deputy consul before grabbing the asylum seekers, presumed to be North Korean. He also reiterated China's position that the security officers had acted to protect the consulate from persons of unknown identity in accordance with the Vienna convention.
Tokyo denied it gave Chinese security permission to enter its consulate. Japan has formally protested the Chinese incursion and summoned the Chinese ambassador to Japan to the foreign ministry in Tokyo to give an explanation. Japan has gone so far as to demand that the asylum seekers be handed back to the Japanese authorities.
Diplomatic offices are regarded as foreign territory, according to international treaties, and Chinese authorities are not supposed to enter them without permission. During the past month there has been a spree of North Koreans seeking asylum at foreign consulates and embassies in China. Many say they are fleeing political repression and famine conditions that exist in the hardline communist state.
U.S. and Chinese officials are still negotiating the fate of three North Koreans who have sought asylum inside a U.S. consulate in the same city this week. China's official position is that North Koreans are economic migrants, not refugees, and should therefore be repatriated. This is a position the United States and many other countries strongly disagree with.