President Jacob Zuma has cautioned police not to harass or torture innocent citizens.

The president addressed thousands of mourners in the Eastern Cape at the weekend.

They were attending the funeral service of five anti-apartheid activists who were tortured and murdered by security police in the 1980s.

Zuma said no one must be subjected to any form of police brutality in this day and age.

"Given lessons of the past, we also declare our commitment to ensure that our police force is never used to fight political battles as it happened during the apartheid era."

Zuma added police who used brute force would be brought to book.