Why doesn't DELETE + REORG free diskspace (DB2)?

Question

In DB2 I have a table containing large binary data. Now i purged the whole table and ran runstats, reorg, runstats, but the amount of disk space taken does not change. What could be wrong here?

The table resides in its own tablespace which I created as follows:

CREATE BUFFERPOOL "MY_BP" SIZE 250 AUTOMATIC PAGESIZE 4096;
CREATE LARGE TABLESPACE MY_TBS IN DATABASE PARTITION GROUP IBMDEFAULTGROUP PAGESIZE 4096 MANAGED BY AUTOMATIC STORAGE EXTENTSIZE 64 PREFETCHSIZE 64 BUFFERPOOL MY_BP OVERHEAD 10.500000 TRANSFERRATE 0.140000 FILE SYSTEM CACHING;

I deleted/reorged as follows:

DELETE FROM MY_TBL
RUNSTATS ON TABLE MY_TBL WITH DISTRIBUTION AND DETAILED INDEXES ALL
REORG TABLE MY_TBL
RUNSTATS ON TABLE MY_TABLE WITH DISTRIBUTION AND DETAILED INDEXES ALL
ALTER TABLESPACE MY_TBS REDUCE

The table MY_TBL took up 2.5GB before all that and after deleting/reorging it uses only 3 MB less.

FWIW: I'm running DB2/NT v9.5.2.