Security Checks??? 485pending imissyouso2004-12-21 20:47:06

I got reply about my pending 485 from USCIS

"Security checks are being conducted in conjuction with your case. We cannot take any action until the security checks are complete."

What's this mean? Is USCIS or FBI carrying out the checks now? Normally how long can they finish these checks?

Thanks very much for your kind reply.