By Sylvia Westall and Amena Bakr
KUWAIT (Reuters) - Warning of "enormous" dangers, Kuwait urged Arab leaders on Tuesday to resolve a lengthening list of disputes complicating crises such as Syria's war and political strife in the biggest Arab state, Egypt.
The annual summit of the 22-member Arab League also heard an appeal from the U.N. peace mediator for Syria, Lakhdar Brahimi, for an end the flow of arms to the combatants in the war, which has killed over 140,000 people and forced millions to flee.
Brahimi did not name the suppliers, but Saudi Arabia and Qatar are believed to be the main Arab funders of military assistance to rebels in Syria, while non-Arab Iran is the main regional power backing President Bashar al-Assad.
"The whole region is in danger," of being dragged into the conflict, Brahimi said, calling for renewed efforts to find a political settlement to the crisis, now in its fourth year.
Kuwait's emir, Sheikh Sabah al-Ahmed al-Sabah, urged Arab states to solve rifts he said were blocking joint Arab action.
"The dangers around us are enormous and we will not move towards joint Arab action without our unity and without casting aside our difference," Sheikh Sabah, the summit host, said.
He named no country. But he was apparently referring to worsening disputes among Arab states over the political role of Islamists in the region, and over what many Gulf states see as interference in their affairs by Shi'ite Muslim Iran, locked in a struggle for regional influence with Sunni power Saudi Arabia.
The summit follows an unusual row within the Gulf Cooperation Council alliance of Gulf Arab states over Qatari support for Egypt's Muslim Brotherhood, and a spat between Iraq and Saudi Arabia over violence in Iraq's Anbar province.
Gulf states tend to keep their disputes private, making a move by Saudi Arabia, the United Arab Emirates and Bahrain this month to recall their ambassadors from Qatar highly sensitive.
Kuwait has offered to mediate: Shortly before the gathering Kuwait's Sheikh Sabah, smiling broadly, stood between Saudi Crown Prince Salman and Qatar's emir, Sheikh Tamim bin Hamad al-Thani, holding hands with them in an apparent attempt to convey a mood of reconciliation.
But a Kuwaiti official said the dispute between Qatar and its neighbours was not expected to be on the summit's agenda.
"Gulf reconciliation, and Gulf issues are something for inside the Gulf house," said Khaled al Jarallah, Kuwaiti undersecretary for foreign affairs.
Arab summits are often dominated by the Israeli-Palestinian conflict, a unifying topic for Arabs. The "Arab Spring" uprisings that began in 2011 have polarised the region, however.
Syria's war has stirred tensions between Sunni Muslims, notably in the Gulf, and Shi'ites in Iraq, Lebanon and Iran, whose faith is related to that of Assad's Alawite minority.
Reiterating that he saw no military solution to the war, Brahimi said Lebanon was in particular danger of being sucked into the conflict.
This appeared to be a reference to recent clashes between Alawites and Sunnis in northern Lebanon and Sunni militant bomb attacks in areas controlled by Lebanon's Shi'ite Hezbollah which has been helping Assad in his war against Sunni rebels.
Saudi Crown Prince Salman called for "changing the balance of forces" on the ground there, adding that the crisis in Syria had reached catastrophic proportions.
On Monday Lebanon's foreign minister called on Arab states to support the Lebanese army to counter fallout from Syria's war, which he said threatened to tear the country apart.
The meeting was expected also to discuss other challenges such as Iran, which has improved its long-frosty ties with Western powers since the election of President Hassan Rouhani.
Syrian opposition leaders have been lobbying the Arab League to give them Syria's seat on the pan-Arab body, and to push Arab states to approve the delivery of military hardware to them.
In the event, Syria's seat remained vacant at the summit.
The head of the opposition Syrian National Coalition, Ahmed al-Jarba, made a speech appealing for more outside help for the rebels, and chided Arab states for not agreeing to give the coalition Syria's seat, saying this would only embolden Assad.
Jarba asked Arab states to press the international community to provide heavy weapons to "our revolutionaries" and increase humanitarian support to Syrians affected by the conflict.
Syria's Arab allies, including Iraq, Algeria and Lebanon, oppose support for the rebels. They point out that Islamists, including groups linked to al Qaeda, are the strongest force in the armed opposition.
(Additional reporting by Sami Aboudi and Rania El Gamal in Dubai, and Samia Nakhoul and Dominic Evans in Beirut, Editing by William Maclean)