Hamas leader Ismail Haniya has publicly broken away from Syria's President Bashar al-Assad and voiced his support for the Syrian uprising.
Al-Azhar mosque, the Arab Medical Union and other political movements organised a conference in Cairo to condemn Israeli settlers attacks on Palestinians and the brutal crackdown by the Syrian regime on protesters.
Haniya saluted the "the heroic Syrian people who are seeking freedom and democracy".
It was the first clear sign that Hamas, a former ally of Assad, has broken away from its former patron.
The group recently vacated its Syrian headquarters but up to now has refrained from publicly criticising the regime.
The recent rapprochement between the Egyptian Muslim Brotherhood, the Gulf states and Hamas has prompted speculation of a Sunni alliance aimed at lessening Shia power in the region.
Haniya also urged Egyptians to support Palestinians and warned: "We will never acknowledge Israel".
Key speakers in the conference also included Salah Sultan, a leading member of the Muslim Brotherhood and of the International Union for Muslim Scholars, as well as former Syrian parliamentarian Mamon El-Homsi.