NEW DELHI, July 17: India may have to opt for significantly upgrading its missile programme.This indication was given by Defence Minister Mulayam Singh Yadav in a question-answer session with reporters during his two-day visit to Bihar recently.``We will not waste even a moment in taking the right decision if our threat perception and the prevailing security scenario warrants such a step,'' he said in response to a query about the reported successful test-firing of the 800 km range Hatf-III ballistic missile by Pakistan.Yadav also said that the government was aware about the aspersions being cast about the authenticity of the successful test-firing of Hatf-III by Pakistan.``But we cannot sit cross-legged just like that doing nothing on the assumption that doubts had reportedly been cast about the authenticity of the test-firing and thus shy away from taking suitable counter measures,'' he said.National security was the paramount concern of the government and all steps necessary for the purpose, including the upgradation of the missile programme, would be taken and funds made available liberally, the Defence minister said. Yadav's observations assume additional significance as they were preceded by his announcement that Agni missile project had not been shelved.