H1B, H4 Visa

Hi I attended the visa interview in chennai on 16th June .... Discussion went well with VO and he asked me for all documents and asked me a few routine questions and asked me to wait for some time.
Then he called me back after 30 mins and said that no issues with my documents and all necessary docs are there but said admin processing is required and handed me a blue slip with the check box saying "Admin processing required" and handed me all my documents along with passport and said they would contact me for further info.... This was at time when the visa processing was down for close to 10 days.

On June 24th there was an update only on the last updated date but no update to the content on he website..

Please let me any idea how much time it might take.

Thanks for the help