Three rockets exploded around Baghdad on Thursday despite a massive security operation as Shi'ite Prime Minister Nuri al-Maliki hosted the country's first Arab League summit in two decades.
After years of war, Iraq's Shi'ite-led government had hoped the summit would highlight its growing stability and renewed role in the region, where Sunni Gulf nations have long been wary of Baghdad's close ties to Shi'ite power Iran.
One rocket exploded on the edge of the fortified Green Zone where the Arab leaders were meeting.
The blast happened close to the Iranian embassy. The windows of the embassy have been shattered, but there are no casualties, a senior Iraqi security source said.
Two other rockets struck central and western Baghdad, but no casualties were reported. Insurgents often fire rockets and mortars at the Green Zone, which houses ministries and foreign embassies.
U.N. Secretary General Ban Ki-Moon joined Arab leaders at the summit in a former palace of Saddam Hussein, and urged Syrian President Bashar al-Assad to implement a U.N.-backed peace plan to end a year of violence in Syria.
The only high-ranking Gulf Arab leader at the talks was the emir of Kuwait, but his presence was a sign of progress in Iraq's often tense relations with Sunni neighbours.
The summit was twice delayed because of clashes between Baghdad and Gulf governments over a crackdown on Shi'ite protesters by Bahrain's Sunni leadership, with the aid of fellow Sunni monarchies Saudi Arabia and United Arab Emirates.
Sunni power Saudi Arabia sent its Arab League delegate, while Qatar said it had sent a low-level delegation to Baghdad as a message to Iraq's leadership about its relations with Iraq's Sunni minority.
Qatar didn't boycott the Arab League's summit in Baghdad but it tried to signal a message to its Iraqi brothers, Qatar's Prime Minister Sheikh Hamad bin Jassim Bin al-Thani told Al Jazeera television.
Leaders attending were from Sudan, Somalia, Comoros, Djibouti, Lebanon, Palestine, Tunisia, Kuwait and Libya.
In the weeks before the meeting, Iraq pursued a campaign of detente with Gulf nations. Saudi Arabia named its first envoy in two decades, Kuwait reached a $500 million (314 million pounds) deal to end a standoff over debt, and Baghdad paid $408 million to Egyptian workers who fled the 1990-91 Gulf War.
But the summit was being held as Sunni Arab powers and Shi'ite Iran increasingly jockey for influence in the Middle East, split along sectarian lines over Syria's crisis and Western sanctions on Tehran. Gulf Arab states also worry about Iraq's influence over their own Shi'ite communities.
Any expectations that the Maliki government will be able to emerge as a significant regional player are likely to be disappointed, Crispin Hawes at Eurasia Group said. Among its neighbours Iraq is viewed with great suspicion and some fear.
SYRIA TOPS AGENDA
The summit comes as Iraq's power-sharing government, with its Sunni, Shi'ite and Kurdish blocs, crawls back from a crisis following the departure of last U.S. troops in December, nine years after the 2003 invasion.
Maliki in December sought the arrest of one Sunni leader and asked lawmakers to sideline another Sunni deputy in measures that fuelled regional worries Iraq might once again slide into broad sectarian violence.
Many Iraqi Sunnis, who dominated under Saddam, saw the move as an attempt to shore up Maliki's position at their expense.
While violence from Iraq's conflict has ebbed since the days of sectarian carnage in 2006-2007, al Qaeda affiliates and other Sunni Islamist insurgents are still a threat.
Iraq's al-Qaeda claimed responsibility for a series of bombs in Baghdad and other cities last week that killed 52 people, a reminder of their capacity to carry out coordinated attacks.
Thousands of extra troops were drafted in Baghdad for the summit and a maze of checkpoints and roadblocks turned the Iraqi capital into a fortress. The airport was closed and the government declared a five-day holiday to help ease congestion.
Syria's crisis topped the agenda for the summit, with U.N. Ban meeting the leaders to discuss the six-point U.N.-backed peace plan to end the turmoil in Iraq's neighbour.
Ban said Syria's President Bashar al-Assad must live up to his agreement to accept the U.N. proposal, telling him: the world is waiting for commitments to be translated into action.
Arab League members have endorsed special envoy Kofi Annan's six-point plan that calls for a ceasefire and peace talks in Syria, but they remain sharply split over how to deal with the violence that risks deepening sectarian divisions.
Sunni powers Saudi Arabia and Qatar have led the push to isolate Syria, but non-Gulf Arab states such as Algeria and Shi'ite-led Iraq urge more caution, fearing that toppling Assad could spark sectarian violence.
(Writing by Patrick Markey; Editing by Serena Chaudhry and Andrew Roche)