solaris 10: device busy when running dladm delete-aggr

aggr1 previously created composed of igb0 and nxge0
then i removed igb0 from the aggr1 and now I have the following and I want to remove the full aggration:

bash-3.2# dladm show-aggr
key: 1 (0x0001) policy: L4      address: 0:10:e0:1e:53:4c (auto)
           device       address                 speed           duplex  link    state
           nxge0        0:10:e0:1e:53:4c          1000  Mbps    full    up      attached

bash-3.2# dladm delete-aggr 1
dladm: delete operation failed: Device busy

!! aggr1 not plumbed at all

bash-3.2# ifconfig -a
lo0: flags=2001000849<UP,LOOPBACK,RUNNING,MULTICAST,IPv4,VIRTUAL> mtu 8232 index 1
        inet 127.0.0.1 netmask ff000000
igb0: flags=1000843<UP,BROADCAST,RUNNING,MULTICAST,IPv4> mtu 1500 index 2
        inet 131.176.73.65 netmask ffffff00 broadcast 131.176.73.255
        ether 0:10:e0:20:33:f2