* Arabs condem Israeli assault on Gaza as "terrorism"
* Arab Spring means Israel has lost ally Egypt
* Calls for governments to take strong action
Israel's bombardment of Gaza has stirred anger across the Middle East among populations who hope that Arab uprisings can translate into a tougher stance against Israel.
Television footage of Israeli airstrikes and pictures of civilian casualties, including four children killed on Sunday, have fuelled rage in the region.
In six days of hostilities, 100 Palestinians have died in Gaza, while three Israelis have been killed by rocket fire from the blockaded coastal territory.
The violence echoes Israel's invasion of Gaza four years ago. But since then, revolutions in North Africa have brought Islamist allies of Gaza's Hamas rulers to power, changing the political map and raising expectations of a more robust Arab response.
"In every Arab state where the nation is rising up to demand its rights, it is also demanding the rights of Palestinians," Egyptian novelist Ahdaf Soueif wrote in al-Shorouk newspaper.
More than 500 Egyptian activists crossed into the Gaza Strip on Sunday to show solidarity with Palestinians, something unthinkable under former president Hosni Mubarak, who kept Egypt's border with Gaza closed during the bloodiest days of the 2008-2009 Israeli air raids and land invasion.
Mubarak was overthrown last year and his successor Mohamed Mursi, whose Muslim Brotherhood is closely linked to Hamas, sent his prime minister to Gaza on Friday.
"For us to mobilise, and not close our ears and close the crossing like what used to happen before, is something good," said Islam Mahmoud, a 30-year-old engineer speaking in Cairo.
"A military confrontation is very difficult now, but there are a lot of things that Arabs can do like pressuring countries that have interests with us to call on the U.S. and others to stop Israel's savage assault."
Wary of Israel's military superiority, few voices are calling for an armed Arab response. But Lebanese militant group Hezbollah has called on Arab states to raise oil prices to pressure Israel.
A prominent Saudi cleric said Cairo should send arms to Gaza's Hamas rulers.
"We call on the Egyptian government to open its borders to all people to come in and out of Gaza, as well as products, medicines and advanced weapons," cleric Awad al-Qarni, who has more than 273,000 followers on Twitter, wrote on his account.
Palestinians demonstrating in the West Bank, home to Palestinian President and Hamas rival Mahmoud Abbas, have demanded the armed wing of Hamas, the Izz el-Deen al-Qassam brigades, take revenge.
"Al Qassam, strike Aviv," they chanted. "Hamas will shake the ground."
In Libya's capital Tripoli, a taxi driver who gave his name as Mohammad said he was shocked by what was happening in Gaza.
"This is not just a problem for Palestinians - the whole world should intervene."
The head of the Arab League and a group of Arab foreign ministers will visit Gaza on Tuesday in the latest official display of solidarity with the 1.7 million Palestinians there.
"The barbaric bombardment we saw yesterday of Gaza children is a crime against humanity," Lebanese Foreign Minister Adnan Mansour, who will join the ministerial trip, told Reuters.
"The world must not stand silent. This is a terrorist act by all standards," he said.
Palestinians deserved a "courageous and honourable stand" from Arab governments, Mansour said.
Despite the rhetoric, the violence in Gaza has not prompted demonstrations on the scale of the uprisings which toppled four Arab leaders last year, threaten Syria's President Bashar al-Assad and may be taking hold in its neighbour, Jordan.
Adel Soliman, head of the International Centre for Future and Strategic Studies in Cairo, said the sweeping political changes in the Arab world had not shifted the balance of power.
"The Middle East is changing, yes, but only in the political structures that are starting to form. The new structure is not stable and the capabilities are the same".
Jordanian Islamist Jamil Abu Bakr said Arab states should do more.
"Although the Arab stance after the Arab spring is different from before, even now the steps taken - important as they are - are not sufficient to stop the aggression," he said.
Jordan and Egypt are the only Arab countries to have signed peace treaties with Israel. Egypt recalled its ambassador from Tel Aviv last week while Jordan, which has not pulled its envoy out, called for an end to "the targeting of civilians".
"This matter will only lead to more tensions in the area and will lead to an explosion of the situation," Foreign Minister Nasser Joudeh said.
In Turkey, a photograph showing the burnt body of a three-year-old girl was widely shared on Twitter under the caption "Ranan Yousef Arafat. 3 years. Killed today by IsraHell."
Ties between Israel and Turkey, once Israel's only Muslim ally, crumbled after Israeli marines stormed an aid ship in 2010 to enforce a naval blockade of the Gaza Strip. Nine Turks were killed in clashes with activists on board.
Qatar, whose leader broke the international isolation of Hamas with a visit to Gaza last month, said the U.N. Security Council should take "a clear position to restore rights to people (in Gaza)".
"What is happening in Gaza is unacceptable on an Arab level," Qatar's Prime Minister Sheikh Hamad bin Jassim al-Thani said in Doha. "We are for a cease-fire, but it has to come about in a clear manner. It has to be by both sides."