Rajya Sabha Chairman Hamid Ansari on Monday rejected Bharatiya Janata Party's demand for a discussion on the Indo-US nuclear agreement under Rule 168 which entails voting, saying Parliamentary nod is not necessary for an international treaty.

"Since it is not a Constitutional obligation for the executive to have the approval of Parliament on any international treaty or agreement, admittance of these motions which involve approval of Parliament will not be in order," he said in his ruling.

Ansari said he had received several notices under Rule 168 on matters pertaining to the nuclear agreement.

He said in some of the motions a demand has been made to disapprove or reject the agreement or have a vote of the House on it.

In other cases, a demand has been made for renegotiation of the agreement, Ansari said adding, there are other notices under Rule 168 demanding a discussion on the agreement.

The chairman said he is converting the notices into notices for discussion under Rule 176.

The Business Advisory Committee has already identified the subject for discussion, he said.