The Green Zone, on the west side of the Tigris, is Baghdad's most secure area but has been a frequent target for rockets and mortar bombs.
The strikes have become more frequent and more accurate recently.
A mortar attack last week killed one employee of a hotel in the zone. There were also a number of casualties in April and May.
On April 12, a suicide bomber killed one politician in the parliament building in the worst breach of security in the zone since the March 2003 invasion to topple Saddam Hussein.