At least 300,000 people have turned out in Gaza City for a rally to mark 20 years since Hamas was founded.

Waving green flags and banners, crowds of Palestinian men, women and children filled a large square for the event.

Analysts say the turnout is seen as a vital test of support for Hamas, which seized control of the Gaza Strip in June from its Fatah rivals.

In a defiant website statement, Hamas's leader in exile, Khaled Mashaal, vowed the group would not renounce violence.

Speaking from Damascus, Syria, he said Palestinians were capable of mounting a new uprising against Israeli occupation, like the intifadas of 1987 and 2000.