RMAN throws RMAN-01009: syntax error: found "double-quoted-string": expecting one of: "backed, compl

 RMAN> DELETE BACKUP "+BACKUP/orion/backupset/2010_06_25/nnsnf0_tag20100625t004700_0.2607.722566021" DEVICE TYPE disk;
RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-00558: error encountered while parsing input commands
RMAN-01009: syntax error: found "double-quoted-string": expecting one of: "backed, completed, controlfile, device, like, of, ;, tag"
RMAN-01007: at line 1 column 15 file: standard input

Whats the correct command?

Regards