Replying to opposition's criticism as to how BJP President Amit Shah could know that 300-350 militants were killed in the Balakot air strike, Union Law Minister Ravi Shankar Prasad on Tuesday said it was an "estimate" and that the government may give an exact figure."The BJP President would have spoken according to an estimate. The exact number of casualties (of militants) could be greater. The government would speak on it. We should not speculate," Prasad said at a press briefing at party headquarters here."The crux of the matter is that a large-scale and effective attack was carried out which caused extensive damage to the terror infrastructure. And above all, we believe our Air Force," Prasad added.He insisted that "voluminous contemporaneous evidence is available" to prove that the Indian Air Force (IAF) strike carried out on the Jaish-e-Mohammed (JeM)'s Balakot camp on February 26 was "very effective".Responding to another media query about Prime Minister Narendra Modi using the Pulwama martyrs' pictures in the background of a rally, Prasad said there was nothing wrong in that."What is wrong in that? The martyrs' pictures should be hung at every crossing in the country, and must be especially hung outside the residences of (Congress leaders) Digvijaya Singh, Kapil Sibal and P. Chidambaram," he said.