Mr Rijiju, 46, is BJP's old hand for Nagaland affairs, and also the party's election-in-charge in the state.
Last Saturday, at a press conference in Guwahati, Mr Rijiju had claimed that sovereignty and "other serious issues" had been dropped from NSCN(IM)'s charter of demands, but on Monday evening, the rebel group hit out at the minister through an official press statement where it claimed it was unbecoming of Mr Rijiju to have made such statements of the on-going negotiation "to which he is incompetent to comment."
NSCN (IM) further claimed that "repeated immature statement" of Mr Rijiju was creating a lot of confusion and thereby vitiating the environment of the negotiation.
When the talk was progressing at the highest level, NSCN(IM) said Mr Rijiju had no business to talk on political issues of which he was ignorant.
"It is demeaning of him to denigrate the Indo-Naga talk which is being held at the Prime Ministerial level. At no point of the negotiation have both the parties ignored important political issues, and the concocted statement of Mr Rijiju that, 'NSCN has 'dropped' the stand of the Nagas on their sovereign right' is a figment of his own imagination," the NSCN(IM) statement added.
It was in August 2015 that the framework agreement between the centre and NSCN(IM) for a final peace deal was signed and it is seen as one of the major success of Prime Minister Narendra Modi's government in the Northeast.
Last year, the centre also brought other Naga rebel groups barring the NSCN(K), that has abrogated its ceasefire agreement with New Delhi, to the ambit of the Naga peace deal to turn it into a more inclusive one.