Suppression of facts and termination from Government service

Regarding NOC for central government employee Hello I working 4600 GP post in central government .I selected 5400 GP post in Central another central government institution without NOC from present employer, wher in the 5400 GP post application , interview and document verification I did not mentioned as i am central government employee as well as not intimated to present employer ,along with this connection the duration of experience certificate attached new post is overlapping to present working duration wich is mandatory and essential requirements hence i did not intimated to the present employer so i have not applied for No objection certificate .All though i approached for NOC but didn't get .In attestation documents shall I mention the previous employer details? Is this looks suppression of metrail facts ? Do I terminate if new employer come to know about my previous employment details through Permanent Retirement account Number.