The Chinese mainland's national security authorities' Thunder 2020 Crackdown has unearthed hundreds of espionage cases involving spies from Taiwan, Chinese national broadcaster China Central Television (CCTV) reported on Sunday.

The activities included attempts to disrupt cross-Straits exchanges, sponsor Hong Kong separatists, and instigate trouble in diplomatic ties between the People's Republic of China and other countries.

The national security authorities have also carried out Thunderbolt 2018 crackdown two years ago, which has identified more than 100 espionage cases.