In LTE, two levels of security is enforced for an UE. MME is responsible for enabling NAS level security, it also sends essential information to eNodeB which is used to activate access stratum (AS) security after successful activation of NAS security. That means NAS security is activate first then access security. If AS security activation fails then UE moves from RRC-CONNECTED to RRC-IDLE state and it tries fresh RRC connection establishment.
Note: If AS security succeed and after that UE looses the radio connection with eNodeB, it tires to resume the lost connection using the RRC connection re-establishment procedure.