The U.S. military in Iraq says two American civilians have been killed in what appear to be separate incidents inside Baghdad's heavily fortified Green Zone.

A military spokesman Saturday said the body of an American civilian who worked for the U.S. Defense Department was found in the Green Zone Friday. 

The spokesman said authorities are investigating the death.  He gave no further details and did not identify the person.

Other sources in the Green Zone said the civilian appeared to have been killed.

In the second incident, the military said another American civilian Defense Department employee was killed by a rocket attack late Friday near the U.S. Embassy.

The two civilian deaths came as Iraqi officials have been tearing down the high concrete blast walls surrounding the Green Zone, which houses the U.S. Embassy and several Iraqi government ministries.

The U.S. military handed control of the Green Zone to the Iraqi army at the beginning of the year.  It was the first step in a new security deal that calls for U.S. forces to withdraw from the country by 2011.

Some information for this report was provided by AFP, AP and Reuters.