L1b blanket petetion

[shiv_11]

HI, I HAVE APPLIED FOR AN L1B BLANKET PETITION IN us embassy London. THE Visa officer said we need to go through the background check and if approved u will get ur visa in 5 working days. now i hve checked the status of my application and it is shown that Your visa case is currently undergoing necessary administrative processing. Can anyone explain wht does that mean. ......or anyone have such experience on L1B BLANKET PETEION

THANKS