The Syrian conflict takes centre stage at an Arab summit starting Tuesday in Kuwait, where a regional rift over Egypt's Muslim Brotherhood has been kept off the agenda.
The dispute which broke out in the runup to the summit pits Qatar against Egypt, Saudi Arabia, Bahrain and the United Arab Emirates.
With the focus on Syria, its opposition National Coalition (NC) head Ahmad al-Jarba is due to address Arab leaders at the opening session.
But the NC will not fill Syria's vacant seat -- which it was allocated at the last Arab summit held in Doha in 2013 -- because it has yet to meet the legal requirements, said Arab League chief Nabil al-Arabi.
The UN-Arab League mediator on Syria, Lakhdar Brahimi, will also brief leaders of the 22-member League on the dim prospects of a political settlement after the failure of two rounds of Geneva peace talks.
He said Monday that a further round of peace talks between the Syrian regime and the opposition was "out of the question for the time being".
Brahimi broke off the last round of the so-called Geneva II talks on February 15 without setting a date for further negotiations.
The conflict in Syria, which in mid-March entered a fourth year, has killed more than 140,000 people and displaced millions.
The Syria government's brutal repression of protests which erupted in March 2011 resulted in its suspension from the Cairo-based Arab League.
Arab foreign ministers at a preparatory meeting on Sunday urged the UN Security Council to pass a resolution under Chapter 7, which threatens the use of force, ordering a ceasefire.
The rift among Arab countries has apparently affected the level of representation at the summit, which is being held in Kuwait for the first time.
Kuwait said 13 heads of state had confirmed their attendance, with low-profile representation from Kuwait's Gulf partners.
The UAE, whose President Sheikh Khalifa bin Zayed Al-Nahyan has not made a public appearance since he underwent an operation following a stroke in January, is sending the ruler of the small emirate of Fujairah.
Saudi Arabia's ailing King Abdullah will be represented by Crown Prince Salman bin Abdulaziz.
Oman, whose leader Sultan Qaboos normally stays away from summits, is dispatching his special envoy, while Bahrain is sending the crown prince, Salman bin Hamad Al-Khalifa.
Apart from Kuwait, only Qatar among the Gulf states is being represented at the level of head of state.
Efforts to settle the inter-Arab rift appear to have been placed on the back burner, with officials ruling out any compromise being struck in Kuwait.
Egyptian Foreign Minister Nabil Fahmi told reporters it was not possible to forge a compromise with Qatar during the summit because "the wound is too deep."
Kuwait's foreign ministry undersecretary Khaled al-Jarallah also said the dispute between Qatar and its neighbours would "be resolved within the Gulf house", not at the Arab summit.
The issue of disputes between Arab countries was not even raised at the ministerial meeting on Sunday, said Iraqi Foreign Minister Hoshyar Zebari.
"There were no controversial issues or problems, and the atmosphere was very positive," he said.
Saudi Arabia, the UAE and Bahrain have recalled their ambassadors from fellow Gulf Cooperation Council member Qatar in protest at Doha's perceived support for the Muslim Brotherhood, branded a terrorist organisation by Cairo and Riyadh.
On the Palestinian issue, Arab leaders are expected to call for $100 million in monthly aid for the Palestinian Authority and to reject recognition of Israel as a Jewish state.
Palestinian leader Mahmud Abbas, fresh from talks with US President Barack Obama in Washington last week, is to brief his Arab counterparts.