BEIJING — China's growing economic clout, Prime Minister Naoto Kan's diplomatic inexperience and strained Japan-U.S. ties are behind Beijing's unusually tough response to the arrest of a fishing boat captain near the disputed Senkaku Islands in the East China Sea, according to some foreign policy observers.

China has "more cards in hand than the Japanese, as their economy is largely dependent on China," Zhou Yongsheng, a professor of Japanese studies at China Foreign Affairs University, was quoted as saying in the Monday issue of the China Daily. "China should take strong countermeasures."

Beijing has suspended exchanges "at and above" ministerial levels and other bilateral activity after an Okinawa court on Sunday authorized extending the detention of the skipper until Sept. 29 for further investigations into the Sept. 7 incident.