A parliamentary delegation from Prime Minister Nuri al-Maliki's own coalition (mainly now the Da`wa Party and the Islamic Supreme Council of Iraq) defied him by going off to the holy seminary city of Qom in Iran and negotiating directly with Sayyid Muqtada al-Sadr and with the leader of the Quds Brigades of the Iranian Revolutionary Guards, Brig. Gen. Qasim Sulaymani.
As a result of those parleys, Muqtada al-Sadr called on his followers to stand down, though I read his statement as permitting continued armed self-defense, as at Basra where the Iraqi Army is attacking them and the US is bombing them. Significantly, he calls on the Mahdi Army to stop attacking the HQs of rival political parties. That language suggests that the parties are suffering from such attacks and are worried that party infrasture is being degraded ahead of the October 1 provincial elections. The southern parties have essentially defied al-Maliki and Bush to make a separate peace.
The entire episode underlines how powerful Iran has become in Iraq. The Iranian government had called on Saturday for the fighting to stop. And by Sunday evening it had negotiated at least a similar call from Sadr (whether the fighting actually stops remains to be seen and depends on local commanders and on whether al-Maliki meets Sadr's conditions).
http://www.juancole.com/2008/03/iran-brokers-call-for-ceasefire-bush.html