Verisign is the Registry. They run "A" root-server and .com and .net They are in the US.
If you want to disable a .com domain, you need to delete the zone for that domain from the .com database.
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 640
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 0
;; QUESTION SECTION:
;com. IN A
;; AUTHORITY SECTION:
;; Query time: 156 msec
;; SERVER: 196.200.16.2#53(196.200.16.2)
;; WHEN: Tue Oct 11 20:16:58 2011
;; MSG SIZE rcvd: 94
; (1 server found)
;; global options: printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 348
;; flags: qr rd; QUERY: 1, ANSWER: 0, AUTHORITY: 2, ADDITIONAL: 2
;; QUESTION SECTION:
;; AUTHORITY SECTION:
;; ADDITIONAL SECTION:
;; Query time: 562 msec
;; SERVER: 192.5.6.30#53(192.5.6.30)
;; WHEN: Tue Oct 11 20:16:59 2011
;; MSG SIZE rcvd: 116