Two of the blasts were near the Iranian Embassy but there has been no immediate official confirmation or explanation of the explosions, the BBC reported.
Eight of the Arab League's 22 leaders gathered in Baghdad the daylong summit, where security was tight and an all-day curfew was in place.
The U.N.-Arab League plan presented by former U.N. Secretary-General Kofi Annan would see a U.N.-monitored end to fighting in Syria, a withdrawal of troops from opposition areas and access for humanitarian services. Syrian President Bashar Assad agreed to the initiative Tuesday but fighting has continued.
The Arab leaders wouldn't ask Assad to step down, Iraqi Foreign Minister Hoshyar Zebari told Middle East Online.
"The Arab League initiative is clear and did not demand that Bashar step down," Zebari said after a ministerial meeting.
Zebari said it was "up to the people of Syria to decide, to choose, to elect their leaders. It's not up to the league or to anybody else."
He said summit participants didn't discuss arming Syrian rebels, Middle East Online said.
U.S. officials have urged countries keep pressure on Assad to end the violence against protesters who have been calling for his ouster for more than a year.
Much of Iraq's capital city was at a standstill because of tight security for the summit, which cost an estimated $500 million to stage.
Afifi Abdel Wahab, Egypt's Arab League ambassador, said the organization's next summit would be in Doha, the Qatari capital.
Meanwhile, U.S. Secretary of State Hillary Clinton was to arrive Friday in Riyadh, Saudi Arabia, for two days of talks with Saudi and other Persian Gulf leaders before meeting Sunday with Arab, Turkish and Western officials in Istanbul, Turkey.