New Delhi: With BJP and Left stepping up their opposition to the Indo-US nuclear deal, Prime Minister Manmohan Singh is likely to intervene in the debate on the issue in Parliament on December 18.

"The Prime Minister may intervene in the debate on civil nuclear issue debate on December 18," Parliamentary Affairs Minister P R Dasmunsi told reporters here.

Dasmunsi, however, made it clear that External Affairs Minister Pranab Mukherjee would reply to the debate.