BAGHDAD (AP) — The annual Arab summit meeting opened in the Iraqi capital Baghdad on Thursday with only 10 of the leaders of the 22-member Arab League in attendance and amid a growing rift between Arab countries over how far they should go to end the one-year conflict in Syria.

As the summit opened, two explosions were heard in central Baghdad.

A senior Iraqi intelligence official said a mortar hit near the Iranian Embassy, just outside the Green Zone where the summit was being held in a palace once used by dictator Saddam Hussein. He had no word on a second explosion and said there were no immediate reports of casualties.

The official spoke on condition of anonymity because he was not authorized to release the information.

Iraq had hoped that hosting the summit would herald its return to the Arab fold after two decades of isolation, but the absence of more than half of the Arab leaders and the ability of militants to launch attacks despite a massive security operation suggest that Iraq may still have some way to go before it could fully return to normalcy and reintegrate into the Arab world.

The emir of Kuwait was the lone head of state to attend from the six U.S.-allied Gulf Arab nations.

The absence of five Gulf Arab leaders reflects increased Sunni-Shia tensions across the region in the aftermath of last year's Arab Spring uprisings, particularly the one against a regime dominated by a Shiite offshoot sect in Sunni-majority Syria and another by majority Shiites in Sunni-ruled Bahrain, also a Gulf Arab nation.

Qatar's Prime Minister Sheikh Hamad Bin Jassem Bin Jabr Al Thani, also the country's foreign minister, told Al-Jazeera late Wednesday that his own nation's low level of representation was a "message" to Iraq's majority Shiites to stop what he called the marginalization of minority Sunnis.

Majority Shiites have dominated Iraq since the 2003 ouster of Saddam Hussein, a Sunni. The nation's once powerful Sunnis complain that the Shiite-led government of Prime Minister Nouri al-Maliki is concentrating power in the hands of the Shiites. There is a growing desire by Sunni-majority provinces to win autonomy as a way to escape Shiite domination.

Tens of thousands of Iraqis died in the sectarian violence that began shortly after Saddam's ouster but peaked in 2006 and 2007. Tension continues to simmers to this day, with occasional attacks by Sunni militants against Shiites and crackdowns on Sunni areas by the Shiite-led security forces.

"Qatar wants the Iraqi government to resolve this in a way that unites the Iraqi people and gives everyone their rights through a dialogue involving all parties," said the Qatari prime minister.

Iraq is hosting the annual Arab summit for the first time since 1990, keen to show it has emerged from years of turmoil and U.S. occupation. But the Syria issue has clouded its attempts to win acceptance by other Arab nations, which are deeply suspicious of its ties with Iran.

Relations between Iraq and the Gulf Arab nations have also been tense over criticism by Shiite Iraqi politicians and clerics of Bahrain's crackdown on Shiite protesters. The demonstrators seek more economic opportunity and an end to what they see as discrimination by the Sunni ruling family.

Al-Maliki on Wednesday met with Bahrain's foreign minister on the sidelines of the Arab summit and Iraqi Foreign Minister Hoshyar Zebari later told reporters that Bahrain would not be on the summit's agenda, a decision that appeared to be a concession by the hosts.

Offering a glimpse of Qatar's thinking on the Syrian crisis, Sheikh Hamad said it would be a "disgrace to all of us if the sacrifices of the Syrian people go to waste."

"We are faced with a difficult choice — either we stand by the Syrian people or stand by him (Assad)," he said. "It is not to be expected from the Syrians to idly stand by while the regime continues to kill its own people this way."

The Gulf nations, particularly Saudi Arabia and Qatar, have been pushing behind the scenes for more assertive action to end the conflict. Privately, they see little benefit in the Arab League's efforts to reach a peaceful settlement and prefer instead to see a small core of nations banding together to act on their own.

Among the options they are considering are arming the Syrian rebels and creating a safe haven for the opposition along the Turkish-Syrian border to serve as a humanitarian refuge or staging ground for anti-regime forces. Such a step would require help from Turkey — the country best positioned to defend such a safe haven — but so far Ankara has seemed reluctant.

For Gulf nations, removing Assad would almost certainly break Syria's alliance with Iran, disrupting the sphere of Tehran's influence that now extends from Iraq and across Syria to the shores of the Mediterranean. Syria's Sunni majority makes up the bulk of the uprising. Assad's regime is dominated by his own Alawite sect, a minority offshoot of Shiite Islam.