Al-Zaman reports in Arabic that on Saturday night into Sunday morning, a Shiite millenarian militia calling itself "The Army of Heaven" (Jund al-Sama') attempted to move south from the Zarqa orchards just north of Najaf to assassinate the four grand ayatollahs of Najaf-- Ali Sistani, Bashir Najafi, Muhammad Ishaq Fayyad and Muhammad Said al-Hakim. The holy city of Najaf, where Ali is buried, is the seat of Shiite religious authority in Iraq. The militiamen, devotees of an obscure religious leader named Ahmad Hassaani, are said to have infiltrated the area from Hillah, Kut and Amara. The well-armed, black-clad militiamen were heard to call upon the Mahdi, the awaited Promised One of the Muslims, to return on that night.
This group is not the Mahdi Army of Muqtada al-Sadr, which bears no enmity toward the grand ayatollahs, but rather a separate and different sect altogether. Shiite clerics told the NYT that the sect is the Mahdawiya of Ahmad al-Basri (possibly Ahmad Hassaani al-Basri?). Although the NYT was told that this millenarian sect (it believes that the end of time is around the corner) was supported by Saddam, you can't pay any attention to that sort of allegation when it comes to Iraqi sectarianism.
It seems most likely that this was Shiite on Shiite violence, with millenarian cultists making an attempt to march on Najaf during the chaos of the ritual season of Muharram. But who knows? It is also possible that the orthodox Shiites in control of Najaf hate the heretic millenarians and the threat of the latter was exaggerated. Darned if I know. The reports of the Army of Heaven being so well armed make no sense if it was a ragtag millenarian band. But those reports could be exaggerations, too.
For those keeping score at home, the United States is supporting a middle east government beholden to Shiite extremists. The extremists have been successful so far in their campaign of ethnic cleansing against the Sunni majority, which the US wants to stop by lending military assistance to the security forces that have been instrumental in ethnic cleansing. This is because al Qaeda, a extremist Sunni idealogy, attacked us on 9/11, and the Iraqi Sunnis don't like al Qaeda, except when foreign fighters are attacking Americans and Shiites.
I think that covers most of it.