CHIANG MAI, Thailand — China has arrested a U.S. citizen on suspicion of spying, the Chinese government said Friday. Min Zin, who heads a think tank focused on his native country of Myanmar, was detained on arrival at Kunming airport in China's southwest Yunnan province on June 3, according to sources including diplomats in the region who are familiar with the arrest.They spoke to NPR on condition of anonymity because of the sensitivity of the case, which they were not authorized to discuss.