Chenyue Mao was prevented from leaving China in recent weeks
Foreign ministry says Mao is required to cooperate in an investigation
No details released on case or Mao's alleged involvement
Mao is a managing director with Wells Fargo
Adds Wells Fargo request for comment in paragraph 3 and background on Mao and Wells Fargo in paragraphs 8-10
BEIJING, July 21 (Reuters) - China's foreign ministry said on Monday Chenyue Mao, the Wells Fargo WFC.N banker who has been blocked from leaving the country, was involved in a criminal case and was obliged to cooperate with the investigation.
Chinese law enforcement authorities have restricted Mao's exit in accordance with the law, Guo Jiakun, a spokesperson for the ministry, told a regular press briefing.
Wells Fargo did not respond to a request for comment from Reuters sent outside normal U.S. business hours. On Friday, the firm said it was "working through the appropriate channels" to secure Mao's return to the United States.
The U.S. bank suspended all travel to China after Mao's exit ban, a person familiar with the matter told Reuters last week, saying she was a U.S. citizen. It is not known exactly when the ban was imposed.
The case was being investigated and Mao was obliged to cooperate with the investigation, Guo said, without elaborating on the case or how the banker was alleged to be involved.
"Everyone in China, whether they are Chinese or foreigners, must abide by Chinese laws," Guo said, adding that China will protect their legitimate rights and interests in investigations.
Mao, who was born in Shanghai and based in Atlanta, is a managing director at Wells Fargo, specialising in the international factoring business.
She has been with the bank for 12 years, according to her LinkedIn profile, and two weeks ago was elected chair of FCI, a global organisation for factoring and financing for domestic and international trade.
Mao leads Wells Fargo's international factoring business, a financing method where companies sell their receivables to third parties, such as banks, in exchange for immediate cash, and advises multinational clients on cross-border working-capital strategies, according to an FCI release.
Wells Fargo's China business is much smaller than its Wall Street peer with two branches in Beijing and Shanghai, according to the units' business registration.
(Reporting by Liz Lee; writing by Scott Murdoch and Beijing Newsroom; Editing by Muralikumar Anantharaman and Kate Mayberry)