BJP chief Rajnath Singh, who is in Guwahati, said that he had requested former deputy Prime Minister L K Advani, who led the Ram temple movement in the late 1980s and the early 1990s, to discuss the matter with party office-bearers.
"The government has set in motion the process of questioning religious beliefs. We will launch a nationwide movement if it does not withdraw immediately this blasphemous submission questioning the very existence of Lord Ram," Singh said.
He also accused the government of insulting the Constitution, which he said contained images of Ram, Sita and Hanuman.
"The government has made an assault on Hindu sentiments, which cannot be tolerated at any cost," the BJP chief said.
Singh alleged that the Congress-led government had no regard for Mahatma Gandhi's "Ram rajya" call.
On Wednesday night, Advani lodged his protest with Prime Minister Manmohan Singh, when he met him over dinner in the Hyderabad house.
"I told the Prime Minister that the affidavit was highly objectionable. I met the Law Minister also and told him that it should be immediately withdrawn," the former deputy prime minister said after his meeting with Singh.
In election mode, the BJP has drawn a parallel between the row over the Sethu Samudram shipping canal project and its Ram temple movement, saying it found similarity in the ruling Congress' response to the saffron objections in both the cases.