"No to the occupation! No to America!" chanted the demonstrators, who had gathered in Tahrir Square after Shiite leader Moqtada Sadr called for a demonstration "in support of Gaza" and against Israel, an AFP journalist reported.

Protesters waved Palestinian and Iraqi flags while a huge Israeli flag was laid on the ground for the demonstrators to trample on.

"This rally is aimed at condemning what is happening in occupied Palestine, the bloodletting and the violation of rights," said Abu Kayan, an organiser of the protest.

Moqtada Sadr's movement has imposed strict security measures around Tahrir Square, while Iraqi security forces are deployed in large numbers around the rally site.

The firebrand Shiite cleric wields great political influence but is not part of the government.

But the movement of support for Gaza is backed by the Iraqi government, which defends the Palestinian cause.

Israel is in the midst of a war to "destroy" Hamas, after the Palestinian Islamists stormed its southern border at the weekend, shooting dead more than 1,200 civilians in the streets and in their homes.

Israel has since been pounding Hamas targets in the Gaza Strip, where 1,537 people have been killed.

On Friday, the Israeli army gave Gaza City residents to evacuate their homes in 24 hours and head south of blockaded territory "for their safety".