BANGKOK (AP) — Civil society and rights groups in Myanmar say Facebook has failed to adequately act against online hate speech that incites violence against the country's Muslim minority.

Phandeeyar, a digital innovation lab, and five other groups wrote an open letter to Facebook founder and CEO Mark Zuckerberg, challenging his contention in a recent interview that the social media platform had effectively combated hate speech targeting the Rohingya community that's being persecuted in western Myanmar.

Htaike Htaike Aung, executive director of one of the groups, Myanmar ICT for Development Organization, says Facebook has been a useful tool for people in Myanmar to exercise freedom of expression, but it had failed to effectively enforce rules to make it a safe community for all.