In 1931, al-Husseini founded the World Islamic Congress, on which he was to serve as president. Versions differ as to whether or not al-Husseini supported Izz ad-Din al-Qassam when he undertook clandestine activities against the British Mandate authorities. His appointment as imam of the al-Istiqlal mosque in Haifa had been approved by al-Husseini. Lachman argues that he secretly encouraged, and perhaps financed al-Qassam at this period. Whatever their relations, the latter's independent activism, and open challenge to the British authorities appears to have led to a rupture between the two. He vigorously opposed the Qassamites' exactions against the Christian and Druze communities.