Major battle in Najaf

Operations continue, but the situation has calmed considerably.

The Los Angeles Times has the best summary of the confusion in this battle:

Iraqi security officials offered conflicting accounts of the identity and motives of the heavily armed fighters outside Najaf, variously describing them as foreign fighters, Sunni Muslim nationalists, loyalists of executed former dictator Saddam Hussein or followers of a messianic Shiite death cult. Some witnesses reported that the attackers wore colorful Afghan tribal robes.

The New York Times may have the best explanation:

But two senior Shiite clerics said the gunmen were part of a Shiite splinter group that Saddam Hussein helped build in the 1990s to compete with followers of the venerated Shiite religious leader Grand Ayatollah Ali al-Sistani. They said the group, calling itself the Mehwadiya, was loyal to Ahmad bin al-Hassan al-Basri, an Iraqi cleric who had a falling out with Muhammad Bakr al-Sadr — father-in-law of the Shiite leader Moktada al-Sadr — in Hawza, a revered Shiite seminary in Najaf.