"It's a non-violent, peaceful gathering and the aim is to show the international community the suffering of the people of Gaza," Amjad al-Shawa, a Gaza-based organiser, told AFP.
The protest was aimed at marking the first anniversary of Israel's massive offensive in Gaza and the location was chosen in part to highlight ties between the isolated coastal enclave and the occupied West Bank, he added.
Eighty-six international activists were allowed to enter Gaza on Wednesday from Egypt via the Rafah crossing, the only terminal not controlled by Israel, which has been mostly closed since the Hamas takeover of Gaza in June 2007.
Another 1,200 activists from around 40 countries remained in Cairo after the Egyptian authorities declined to allow the entire group to enter Gaza because of what they called the "sensitive situation" in the Palestinian territory.
Scuffles broke out in Cairo as around 200 activists gathered downtown to protest the decision, with Egyptian police punching and kicking protesters, leaving one with broken ribs, organisers said. Read more.