Three of China's top table tennis stars apologized to fans on Sunday after going AWOL at an international tournament and sports authorities have vowed to investigate.

Ma Long, Fan Zhendong and Xu Xin were criticized for tarnishing the national team's image by skipping singles matches on Friday at the ongoing China Open in Chengdu, Sichuan province.

The national team released a statement saying their behavior had disappointed fans and exposed team management problems. The General Administration of Sport of China said the behavior was a breach of professional ethics.