Iraqi Defense Ministry spokesman Gen. Mohammed al-Askari said the former servicemen "volunteered" to return to duty, noting the Iraqi government's favoritism of the move, the Iraqi daily Azzaman reported.

"The return of this large group of members and officers will boost the strength of the armed forces," Askari said.

This is the largest single allocation of former servicemen permitted to return to the new Iraqi military. Azzaman reports it may be an attempt by the Shiite government of Iraqi Prime Minister Nouri al-Maliki to appease Sunnis.

The return comes as Maliki seeks to position Iraqi military forces as a dominant security presence.

The Iraqi military Wednesday entered the stronghold of Shiite cleric Moqtada Sadr largely unassisted by the U.S. military.

Raids against militants operating in the southern port city of Basra and the northern city of Mosul were largely Iraqi operations as well.