Saudi Arabia last month brokered a unity government between Palestinian President Mahmoud Abbas's Fatah faction and Hamas, hoping it would help end a Western financial blockade imposed after the Islamist group took office more than a year ago.
"The new government should show signs of maturity and responsibility"
Husky, Ottawa, Canada
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The summit drew a number of world and Muslim leaders who backed the Arab plan for renewed Arab-Israeli peace efforts.
Ban Ki-Moon, the UN secretary-general, said in an address: "This initiative sends a signal that the Arabs are serious about achieving peace."
Riyadh, pressed by its ally Washington to show more leadership in the region, has called on Muslim states to overcome divisions, arguing a united front will help persuade Israel to address Palestinian grievances.
King Abdullah stressed that Sunni-Shia violence in Iraq threatened the stability of the entire oil-producing Gulf region.
"It has become necessary to end the unjust blockade imposed on the Palestinian people as soon as possible so that the peace process can move in an atmosphere far from oppression and force"
King Abdullah, Saudi Arabia
"In beloved Iraq, blood flows between brothers in the shadow of illegitimate foreign occupation and hateful sectarianism, threatening a civil war," he said, in an unusually strong criticism of the US presence in Iraq from a strong ally.
Pervez Musharraf, the Pakistani president, and one of several world figures invited to the summit's opening session, went further by warning that rising tensions in the Gulf region risked a confrontation that could affect the entire world.
"Tensions in the Gulf region are shaping an ominous confrontation that could have incalculable consequences globally, regionally and among the Muslim umma [faithful].
"We cannot remain helpless spectators in this and other crises and conflicts afflicting the Islamic world... We need to join hands to work for solutions on the basis of fairness, justice and realism."
Amr Moussa, head of the Arab League, pressed Israel to accept unchanged a 2002 Arab initiative being revived at the summit.
"The Israelis' response was to ask for an amendment. We tell them to accept it first," he said.
The Arab peace plan offers the Jewish state normal ties with all Arab countries if it fully withdraws from land it occupied in 1967, accepts a Palestinian state and agrees to a "just solution" for Palestinian refugees.
Israel has objected to key elements in the plan, including the proposed return to 1967 borders, the inclusion of Arab East Jerusalem in a Palestinian state and the return of Palestinian refugees to homes in what is now Israel.
Ismail Haniya, the Palestinian prime minister, urged leaders not to compromise on the right of refugees to return to homes lost in the turmoil surrounding the creation of the Israeli state.
"I expect the Arab summit to reiterate the Arab countries' commitment not to compromise in any way on the Palestinian refugees' right of return under any circumstances."
A final draft resolution calls for a "just solution" to the problem of Palestinian refugees who fled their homes in 1948 but avoids any mention of the phrase "right of return".
Abbas said: "I don't believe there will be another opportunity in the future like this."
The Bahraini president of the UN General Assembly became the first woman to address an Arab summit on Wednesday as she took the podium at the opening session in Riyadh.
Haya Rashed al-Khalifa was the first woman to address an annual summit of the 22-member Arab League since the bloc was formed in 1945.
The 53-year-old was one of the first women to practise law in Bahrain, where she defended women before Sharia courts.