SHANGHAI, June 18 (Reuters) - China securities regulator vowed on Tuesday it will maintain a "zero-tolerance" stance on illegal activities in the capital markets and will include all financial activities in regulation.

The China Securities Regulatory Commission (CSRC) said in a statement it will step up monitoring of trading behavior by key investors and resolutely prevent abnormal stock market volatility.

(Reporting by Shanghai newsroom; editing by Jason Neely)