The BATF is assisting full heartedly, however.
I don't know what role they have in this, but there was a report that a special squad of BATF had gone to New Orleans. I would not be surprised to find out that indeed they are part of the gun confiscation scheme; certainly, it seems hard to imagine that they are there to enforce alcohol or tobacco laws.
Here's one article about the BATFE special squad's exploits; I didn't see anything, though, about confiscation:
KATRINA'S AFTERMATH: Michigan squads lay down law in the South: Agents help round up shooters