At least three powerful explosions hit the edge of the fortified Green Zone in the Iraqi capital Baghdad as the Arab League (AL) summit was kicked off Thursday.

The explosions happened minutes after the summit began its opening session. The scene was reportedly just outside the Green Zone and near the Iranian embassy. There was no immediate report of casualties or damage.

Xinhua correspondents heard three successive blasts in Baghdad' s central district but did not see any smoke column. Local media reported that the explosions were unlikely to be caused by car bombs, but possibly by rockets, mortar rounds or suicide bombers.

Mobile phone network has been shut off and residents are under curfew, which made it difficult for correspondents to gather more information about the explosions.

Security has been largely good in Baghdad since the start of AL meetings on March 27, as thousands of security members were deployed around the city and most places locked down.