Demonstrations in Israel's main regional ally Turkey led swelling Muslim protests Sunday over the ground offensive in Gaza.
However, a demonstration in Paris backing Israel attracted several thousand supporters.
In Istanbul, organizers claimed as many as 700,000 people had turned out for their protest. Police in Turkey refused to give numbers, but central Istanbul's sprawling Caglayan square was packed with a sea of protesters.
"The bastards of the devil, go away from Palestine and the Middle East," said one banner in English.
Thousands of Moroccans rallied in the capital Rabat, accusing Arab leaders of having failed the Palestinian people.
The demonstrators, about 40,000 according to police estimates, chanted expressions of anger over "the silence of Arab regimes."
Protesters also accused Egyptian President Hosni Mubarak of having "sold Gaza for dollars".
Some of the Moroccan demonstrators trampled on a giant Israeli flag, while others brandished shoes in an allusion to the Iraqi journalist who threw his brogues at outgoing US President George W. Bush last month.
US, Israeli flags set aflame
In Lebanon, thousands demonstrated outside the UN headquarters in Beirut.
Lebanese riot police fired teargas and water cannon at about a hundred protesters near the US embassy compound in Awkar, north of Beirut, an AFP photographer said.
In Greece, thousands of people marched for the second day running to protest the Israeli action.
More than 4,000 people joined protests outside the US embassy and the Israeli embassy in Athens, burning effigies of Bush and President-elect Barack Obama and both the Israeli and US flags.
Earlier Sunday hundreds of protesters marched in the northern city of Thessaloniki, burning US and Israeli flags in front of the US consulate.
Thousands of people had already marched in both cities Saturday.
Rallies in US, Canada, Australia
Norwegian police said they had used tear gas to break up a demonstration outside the Israeli embassy in Oslo after the protesters started throwing rocks and eggs at them. Several hundred people took part in the demonstration, according to Norwegian media reports.
A couple dozen pro-Palestinian demonstrators gathered outside the Hays-Adam hotel in Washington to greet Obama as he arrived to prepare his transition and meet his wife and daughters, who came a day earlier.
Some held candles, while others waved Palestinian flags and raised signs that read: "Obama Call for Ceasefire, Please," and "Not in Our Name."
In the Canadian city of Montreal, some 5,000 people according to media estimates, braved the bitter cold to march on the Israeli consulate to demand a halt to Israel's offensive.
This demonstration followed several marches Saturday in Ottawa, Toronto and Vancouver, which also demanded an end to Israeli attacks on Gaza.
In Iraq, some 200 protesters staged a protest in the southern Shiite shrine city of Karbala to condemn Israel and express support for embattled Palestinians.
Earlier Sunday, thousands also marched through central Sydney and the southern city of Melbourne in Australia.