He was speaking after attending a weekly cabinet meeting chaired by Prayut.
Army chief Gen Udomdej Sitabutr added that the prime minister wanted to know who was behind the document, which went viral on the social networks.
Udomdej, who is also deputy defence minister, dismissed speculation that the publication of the document and bomb explosion at Paragon shopping complex on Sunday night could be linked.
He told reporters not to think too much and that police are investigating who were behind the blast.