Lalta Prasad and Rakesh Kumar were taken to Shashtri Bhawan today by the Crime Branch.
Sources, meanwhile, said that police had also stumbled upon another module operated separately from the those arrested so far and their "area of operation" was another plum ministry.
They added that a junior-level officer and some more corporate executives are under scanner in this connection and arrests are expected by Monday.
Sources said that two top officials of a major oil firm were summoned to join investigation but while one is down with swine flu, the other is out of country. Police may soon summon some senior officials for questioning as well.
"We have questioned the people who are in our custody and a team, which included policemen and experts from the ministry, is examining the documents recovered so far.
We also recorded the statement of the key maker who had made the duplicate keys of the ministry locks and he is our "main witness" in the case, he added.
Producing the five corporate executives arrested on Friday before Chief Metropolitan Magistrate Sanjay Khanagwal, the police said, "National interest was taken for a ride in the case.
