Reports have said that he has lost control of some defiant commanders, whose activities could damage the reputation of his bloc and incur suppression from the US troops and the Iraqi security forces, a considerable part of which comprise members of his Shiite rival SIIC.

"Sadr wants to promote better relations with Prime Minister Nuri al-Maliki and his Dawa Party to establish a new powerful Shiite political bloc to replace the current leading parliamentary bloc headed by Abdul Aziz al-Hakim," Shamma said.

Hakim is the leader of the SIIC and the United Iraqi Alliance (UIA), an umbrella Shiite political bloc in the Iraqi parliament.

"Although the SIIC and Sadr movement are both Shiite parties, Sadr has realized that Hakim is trying to kick him and his Mahdi Army out of the political power," Shamma said.

The two powerful parties have been vying for control in the Shiite-dominated south.

"He also wanted to use the new period of lull to get rid of those criminal activists who infiltrated in his Mahdi Army," Shamma said.

Ibrahim al-Amiri, an analyst in Baghdad University said that "the decision is wise and Sadr has just kicked the ball in the field of the government and the other political parties."